Resizing divs and background images to fit page with CSS - css

Say that i want to have a couple of divs on my page with images in the background (like this: http://www.ubudhanginggardens.com/). I know how to set the size of my divs, but the problem is that the background image stays the same if I make the web browser smaller... I want the background image to scale up/down with the web browser.
CSS
body, html {
height: 100%;
width: 100%;
margin: 0px;
}
#container1 {
float: left;
height: 100%;
width: 50%;
background-image: url(../img/1.png);
}
#container2 {
float: left;
height: 100%;
width: 50%;
background-image: url(../img/2.png);
}

This can be done with pure CSS and does not even require media queries.
To make the images flexible, simply add max-width:100% and height:auto. Image max-width:100% and height:auto works in IE7, but not in IE8 (yes, another weird IE bug). To fix this, you need to add width:auto\9 for IE8.
Source
CSS:
img {
max-width: 100%;
height: auto;
width: auto\9; /* ie8 */
}
And if you want to enforce a fixed max width of the image, just place it inside a container, for example:
<div style="max-width:500px;">
<img src="..." />
</div>
jsFiddle example here. No javascript required. Works in latest versions of Chrome, Firefox and IE (which is all I've tested).

If you would like to have your image scale with your browser, set the width to a percent instead of defining it as a number of pixels.
So if you wanted the image to always cover half of a div:
<div class="my_div">
<img src="http://example.com"></img>
</div>
<style>
.my_div .image {
width:50%;
}
</style>
As you change your browser window size, the size of the image will change. You might want to take a look at Responsive CSS Frameworks, such as Twitter's Bootstrap, which can help you achieve exactly this behavior.

Related

Possible to set a max-width for a background image? (want to scale background-image down, but not scale up)

I am using a series of a div elements to display a set of client logos. The reason for using background images was to allow the images to be vertically and horizontally centered within the div, instead of a more hack-y solution using img elements.
The issue: I am using a fluid, responsive grid, so when the browser is below the max width (1000px), the div elements begin to shrink. This causes some of the client logos (the background images) to clip at the edges. This is a given. I would like to have these images begin to scale down when the hit the edges of the parent element.
background-size: contain partially solves this. The only drawback is that it also scales the background image's size above 100%, which is an issue. It stretches the logo which is not a good solution for me.
I could also just not use background-size, and have the client logos have a max-width set. This, however, causes the client list to go to extra rows for responsive layouts. I would like to avoid this, but to me this is the only working solution.
That being said, is there anyway to utilize the background-size without having it scale up? Or is there another way to approach this that would keep the images centered within their box?
Here's quick look at the code:
HTML
<div class="client"><div class="client1"></div></div>
<div class="client"><div class="client2"></div></div>
<div class="client"><div class="client3"></div></div>
CSS
.clientlist .client { width: 20%; height: 90px; float: left; } /* Five clients a row */
.clientlist .client div {
width: 100%;
height: 100%;
background-position: center center;
background-repeat: no-repeat; } /* Vertically centers background images */
.clientlist .client .bcs { background-image: url(../images/client-bcs.jpg); } /* bunch more like this to define image */
It doesn't look like this is possible yet.
Based on the syntax examples on https://developer.mozilla.org/en-US/docs/Web/CSS/background-size#Syntax, you would think you could do something along the lines of "background-size: auto, auto, contain;" but it didn't play out that way in my initial testing on Chrome, FF and IE. They all seem to do fine with SVGs. Chrome and IE fail with PNGs. All of them fail with GIFs.
To me, it seems like this behavior we are looking for is spelled out pretty clearly on http://www.w3.org/TR/css3-background/#the-background-size:
If both values are ‘auto’ then the intrinsic width and/or height of the image should be used, if any, the missing dimension (if any) behaving as ‘auto’ as described above. If the image has neither an intrinsic width nor an intrinsic height, its size is determined as for ‘contain’.
However, it doesn't play out that way so maybe I'm missing something.
I think that this is what your a re asking for
demo
The HTML is
<div class="clientlist">
<div class="client"><div class="client1"></div></div>
<div class="client"><div class="client2"></div></div>
<div class="client"><div class="client3"></div></div>
<div class="client"><div class="client4"></div></div>
<div class="client"><div class="client5"></div></div>
<div class="push"></div>
</div>
And The CSS is
body, html {
height: 100%;
}
.clientlist {
text-align: justify;
display: inline-block;
width: 100%;
}
.clientlist .client {
width: 18%;
height: 90px;
max-width: 200px;
display: inline-block;
}
.clientlist .client div {
width: 100%;
height: 100%;
background-position: center center;
background-repeat: no-repeat;
background-size: contain;
}
.push {
display: inline-block;
width: 100%;
height: 0px;
}
.client1 { background-image: url(http://placekitten.com/200/300); }
.client2 { background-image: url(http://placekitten.com/200/200); }
.client3 { background-image: url(http://placekitten.com/200/180); }
.client4 { background-image: url(http://placekitten.com/220/200); }
.client5 { background-image: url(http://placekitten.com/180/200); }
I am setting the max-width on the div, and not really in the background size; but I think that the result is the intended one.
To make the div space evenly, I use a trick using text-align: justify. For this to work; I need an extra element in the HTML that is the "push" class.

Background image stretch y-axis only, keep repeat-x

I have an image set as a background image of a div. The DIV size is changing and inside their is the image which is a gradient.
CSS:
#scroller_shadow{
background-image:url(../img/ui/shadow.png);
background-repeat:repeat-x;
background-position:top;
}
I need a cross-browser solution for making the image fit the height of the div in the y-axis only, keeping the repeat-x. The DIV is being resized dynamically via JQuery.
Their might be a cross-browser option using JQuery. I don't mind using scripts to achieve that in order to get cross-browser support (IE7+). I don't want to stretch the image because it loses the intensity when you stretch the image on the x-axis, making a semi-transparent png image almost transparent.
Thanks.
I had this problem too. It's easy in most browsers, but IE8 and below it's tricky.
Solution for modern (anything not IE8 and below) browsers:
#scroller_shadow {
background: url(../img/ui/shadow.png) center repeat-x;
background-size: auto 100%;
}
There are jQuery plugins that can mimic background-size for IE8 and below, specifically backgroundSize.js but it doesn't work if you want it to repeat.
Anyways thus begins my terrible hack:
<div id="scroller_shadow">
<div id="scroller_shadow_tile">
<img src="./img/ui/shadow.png" alt="" >
<img src="./img/ui/shadow.png" alt="" >
<img src="./img/ui/shadow.png" alt="" >
...
<img src="./img/ui/shadow.png" alt="" >
</div>
</div>
Make sure to include enough <img>'s to cover the area needed.
CSS:
#scroller_shadow {
width: 500px; /* whatever your width is */
height: 100px; /* whatever your height is */
overflow: hidden;
}
#scroller_shadow_tile {
/* Something sufficiently large, you only to make it unreasonably wide if the width of the parent is dynamic. */
width: 9999px;
height: 100%;
}
#scroller_shadow_tile img {
height: 100%;
float: left;
width: auto;
}
Anyways, the idea is to create the stretch effect from the images.
JSFiddle.
background-position: left top;
background-repeat-y: repeat;
background-size: 100%;

Stretch height to container

I'm trying to make a background following this example, but I need to nest 2 containers.
My code look something like:
XHTML:
<body>
<div id="background_shadow">
<div id="container">
<!--content-->
</div>
</div>
</body>
css:
#background_shadow{
margin:0 auto; /* center, not in IE5 */
height:100%;
height:auto !important; /* real browsers */
min-height:100%; /* real browsers */
width: 876px;
padding: 0px 72px;
background: url("../images/background_shadow.png") repeat-y center;
}
#container{
width: 100%;
margin: auto;
background-image: url("../images/background.jpg") repeat-y;
height: 100%;
}
The problem is that the #container element isn't stretching with #background_shadow. Am I missing something? I would like to use nested container with 2 background image because one of them is transparent and if I use png instead of jpeg on the second image the filesize is too big (around 1Mo)
Here is what I'm getting
And what I would like
I guess that if there arn't any solution I will need to use a big png.
Thank you
For height: 100%; to work on an element, all parent elements need it, too (even html and body). So because of height: auto !important;, it doesn't work anymore in the #container child.
You can either remove the height: auto; or add #container { min-height: 100%; }. I just tested it in Opera 11 and apparently min-height works just as fine. Don't know about IE, though.
By the example you provided, your #background_shadow should have position: relative. That's going to allow it and it's children out of the restrictions of straight document flow.
Use Firebug to delete the footer from your example link - you'll see the div above it expand to fill the page even though it's content does not require the additional height.

How can I resize an image dynamically with CSS as the browser width/height changes?

I wonder how I could make an image resize along with the browser window, here is what I have done so far (or download the whole site in a ZIP).
This works okay in Firefox, but it has problems in Chrome: the image does not always resize, it somehow depends on the size of the window when the page was loaded.
This also works okay in Safari, but sometimes the image is loaded with its minimum width/height. Maybe this is caused by the image size, I am not sure. (If it loads okay, try to refresh several times to see the bug.)
Any ideas on how could I make this more bulletproof? (If JavaScript will be needed I can live with that, too, but CSS is preferable.)
This can be done with pure CSS and does not even require media queries.
To make the images flexible, simply add max-width:100% and height:auto. Image max-width:100% and height:auto works in IE7, but not in IE8 (yes, another weird IE bug). To fix this, you need to add width:auto\9 for IE8.
source: http://webdesignerwall.com/tutorials/responsive-design-with-css3-media-queries
CSS:
img {
max-width: 100%;
height: auto;
width: auto\9; /* ie8 */
}
And if you want to enforce a fixed max width of the image, just place it inside a container, for example:
<div style="max-width:500px;">
<img src="..." />
</div>
JSFiddle example here. No JavaScript required. Works in latest versions of Chrome, Firefox and IE (which is all I've tested).
2018 and later solution:
Using viewport-relative units should make your life way easier, given we have the image of a cat:
Now we want this cat inside our code, while respecting aspect ratios:
img {
width: 100%;
height: auto;
}
<img src="https://www.petmd.com/sites/default/files/petmd-cat-happy-10.jpg" alt="cat">
So far not really interesting, but what if we would like to change the cats width to be the maximum of 50% of the viewport?
img {
width: 100%;
height: auto;
/* Magic! */
max-width: 50vw;
}
<img src="https://www.petmd.com/sites/default/files/petmd-cat-happy-10.jpg" alt="cat">
The same image, but now restricted to a maximum width of 50vw
vw (=viewport width) means the image will be X width of the viewport, depending on the digit provided. This also works for height:
img {
width: auto;
height: 100%;
max-height: 20vh;
}
<img src="https://www.petmd.com/sites/default/files/petmd-cat-happy-10.jpg" alt="cat">
This restricts the height of the image to a maximum of 20% of the viewport.
window.onresize = function(){
var img = document.getElementById('fullsize');
img.style.width = "100%";
};
In IE onresize event gets fired on every pixel change (width or height) so there could be performance issue. Delay image resizing for few milliseconds by using javascript's window.setTimeout().
http://mbccs.blogspot.com/2007/11/fixing-window-resize-event-in-ie.html
Set the resize property to both. Then you can change width and height like this:
.classname img{
resize: both;
width:50px;
height:25px;
}
Are you using jQuery?
Because I did a quickly search on the jQuery plugings and they seem to have some plugin to do this, check this one, should work:
http://plugins.jquery.com/project/jquery-afterresize
EDIT:
This is the CSS solution, I just add a style="width: 100%", and works for me at least in chrome and Safari. I dont have ie, so just test there, and let me know, here is the code:
<div id="gallery" style="width: 100%">
<img src="images/fullsize.jpg" alt="" id="fullsize" />
prev
next
</div>
Initially, I was using the following html/css:
img {
max-width: 100%;
height: auto;
width: auto\9; /* ie8 */
}
<div>
<img src="..." />
</div>
Then I added class="img" to the <div> like this:
<div class="img">
<img src="..." />
</div>
And everything started to work fine.
Just use this code. What most are forgeting is to specify max-width as the max-width of the image
img {
height: auto;
width: 100%;
max-width: 300px;
}
You can use CSS3 scale property to resize image with css:
.image:hover {
-webkit-transform:scale(1.2);
transform:scale(1.2);
}
.image {
-webkit-transition: all 0.7s ease;
transition: all 0.7s ease;
}
Further Reading:
CSS3 2D Transforms
CSS3 Hover Effect Transitions, Transformations, Animations
Try
.img{
width:100vw; /* Matches to the Viewport Width */
height:auto;
max-width:100% !important;
}
Only works with display block and inline block, this has no effect on flex items as I've just spent ages trying to find out.

How to get div height to auto-adjust to background size?

How do I get a div to automatically adjust to the size of the background I set for it without setting a specific height (or min-height) for it?
There is a very nice and cool way to make a background image work like an img element so it adjust its height automatically. You need to know the image width and height ratio. Set the height of the container to 0 and set the padding-top as percentage based upon the image ratio.
It will look like the following:
div {
background-image: url('http://www.pets4homes.co.uk/images/articles/1111/large/feline-influenza-all-about-cat-flu-5239fffd61ddf.jpg');
background-size: contain;
background-repeat: no-repeat;
width: 100%;
height: 0;
padding-top: 66.64%; /* (img-height / img-width * container-width) */
/* (853 / 1280 * 100) */
}
You just got a background image with auto height which will work just like an img element. Here is a working prototype (you can resize and check the div height): http://jsfiddle.net/8m9ur5qj/
Another, perhaps inefficient, solution would be to include the image under an img element set to visibility: hidden;. Then make the background-image of the surrounding div the same as the image.
This will set the surrounding div to the size of the image in the img element but display it as a background.
<div style="background-image: url(http://your-image.jpg);">
<img src="http://your-image.jpg" style="visibility: hidden;" />
</div>
There is no way to auto adjust for background image size using CSS.
You can hack around it by measuring the background image on the server and then applying those attributes to the div, as others have mentioned.
You could also hack up some javascript to resize the div based on the image size (once the image has been downloaded) - this is basically the same thing.
If you need your div to auto-fit the image, I might ask why don't you just put an <img> tag inside your div?
This answer is similar to others, but is overall the best for most applications. You need to know the image size before hand which you usually do. This will let you add overlay text, titles etc. with no negative padding or absolute positioning of the image. They key is to set the padding % to match the image aspect ratio as seen in the example below. I used this answer and essentially just added an image background.
.wrapper {
width: 100%;
/* whatever width you want */
display: inline-block;
position: relative;
background-size: contain;
background: url('https://upload.wikimedia.org/wikipedia/en/thumb/6/67/Wiki-llama.jpg/1600px-Wiki-llama.jpg') top center no-repeat;
margin: 0 auto;
}
.wrapper:after {
padding-top: 75%;
/* this llama image is 800x600 so set the padding top % to match 600/800 = .75 */
display: block;
content: '';
}
.main {
position: absolute;
top: 0;
bottom: 0;
right: 0;
left: 0;
color: black;
text-align: center;
margin-top: 5%;
}
<div class="wrapper">
<div class="main">
This is where your overlay content goes, titles, text, buttons, etc.
</div>
</div>
I looked at some of the solutions and they're great but I think I found a surprisingly easy way.
First, we need to get the ratio from the background image. We simply divide one dimension through another. Then we get something like for example 66.4%
When we have image ratio we can simply calculate the height of the div by multiplying the ratio by viewport width:
height: calc(0.664 * 100vw);
To me, it works, sets div height properly and changes it when the window is resized.
Maybe this can help, it's not exactly a background, but you get the idea:
<style>
div {
float: left;
position: relative;
}
div img {
position: relative;
}
div div {
position: absolute;
top:0;
left:0;
}
</style>
<div>
<img src="http://antwrp.gsfc.nasa.gov/apod/image/0903/omegacen_davis.jpg" />
<div>Hi there</div>
</div>
Pretty sure this will never been seen all the way down here. But if your problem was the same as mine, this was my solution:
.imaged-container{
background-image:url('<%= asset_path("landing-page.png") %> ');
background-repeat: no-repeat;
background-size: 100%;
height: 65vw;
}
I wanted to have a div in the center of the image, and this will allow me of that.
There is a pure CSS solution that the other answers have missed.
The "content:" property is mostly used to insert text content into an element, but can also be used to insert image content.
.my-div:before {
content: url("image.png");
}
This will cause the div to resize its height to the actual pixel size of the image. To resize the width too, add:
.my-div {
display: inline-block;
}
The recently introduced CSS aspect-ratio attribute (~2020-2021) is a great way to do this without padding hacks and is supported on all evergreen browsers.
Since we need to know the aspect ratio of the image ahead of time, and in many usecases you'll be able to predetermine the image dimension ratio ahead of time (but not always for user generated content), you can either hardcode a single style or inline the css when necessary.
aspect-ratio will calculate the height when the width is specified, based on the provided ratio (or calculate width, if the height is specified).
div {
aspect-ratio: 3 / 2; /*common ratio, like an 800*600px image */
width: 200px; /* computed height will be 133.33px, which is width/aspect-ratio */
background: red; /* so any image bleed is shown*/
background-image: url('https://images.unsplash.com/photo-1631163190830-8770a0ad4aa9?ixid=MnwxMjA3fDB8MHxwaG90by1wYWdlfHx8fGVufDB8fHx8&ixlib=rb-1.2.1&auto=format&fit=crop&w=200&q=80');
}
<div></div>
You can do it server side: by measuring the image and then setting the div size, OR loading the image with JS, read it's attributes and then set the DIV size.
And here is an idea, put the same image inside the div as an IMG tag, but give it visibility: hidden + play with position relative+ give this div the image as background.
I had this issue and found Hasanavi's answer but I got a little bug when displaying the background image on a wide screen - The background image didn't spread to the whole width of the screen.
So here is my solution - based on Hasanavi's code but better... and this should work on both extra-wide and mobile screens.
/*WIDE SCREEN SUPPORT*/
#media screen and (min-width: 769px) {
div {
background-image: url('http://www.pets4homes.co.uk/images/articles/1111/large/feline-influenza-all-about-cat-flu-5239fffd61ddf.jpg');
background-size: cover;
background-repeat: no-repeat;
width: 100%;
height: 0;
padding-top: 66.64%; /* (img-height / img-width * container-width) */
/* (853 / 1280 * 100) */
}
}
/*MOBILE SUPPORT*/
#media screen and (max-width: 768px) {
div {
background-image: url('http://www.pets4homes.co.uk/images/articles/1111/large/feline-influenza-all-about-cat-flu-5239fffd61ddf.jpg');
background-size: contain;
background-repeat: no-repeat;
width: 100%;
height: 0;
padding-top: 66.64%; /* (img-height / img-width * container-width) */
/* (853 / 1280 * 100) */
}
}
As you might have noticed, the background-size: contain; property doas not fit well in extra wide screens, and the background-size: cover; property does not fit well on mobile screens so I used this #media attribute to play around with the screen sizes and fix this issue.
This Worked For Me:
background-image: url("/assets/image_complete_path");
background-position: center; /* Center the image */
background-repeat: no-repeat; /* Do not repeat the image */
background-size: cover;
height: 100%;
If it is a single predetermined background image and you want the div to to be responsive without distorting the aspect ratio of the background image you can first calculate the aspect ratio of the image and then create a div which preserves it's aspect ratio by doing the following:
Say you want an aspect ratio of 4/1 and the width of the div is 32%:
div {
width: 32%;
padding-bottom: 8%;
}
This results from the fact that padding is calculated based on the width of the containing element.
Adding to the original accepted answer just add style width:100%; to the inner image so it will auto-shrink/expand for mobile devices and wont end up taking large top or bottom margins in mobile view.
<div style="background-image: url(http://your-image.jpg);background-position:center;background-repeat:no-repeat;background-size: contain;height: auto;">
<img src="http://your-image.jpg" style="visibility: hidden; width: 100%;" />
</div>
How about this :)
.fixed-centered-covers-entire-page{
margin:auto;
background-image: url('https://i.imgur.com/Ljd0YBi.jpg');
background-repeat: no-repeat;background-size:cover;
background-position: 50%;
background-color: #fff;
left:0;
right:0;
top:0;
bottom:0;
z-index:-1;
position:fixed;
}
<div class="fixed-centered-covers-entire-page"></div>
Demo: http://jsfiddle.net/josephmcasey/KhPaF/
I would do the reverse and place the image inside of the main div with a width of 100%, which will make both the div and image responsive to screen size,
Then add the content within an absolute positioned div with width and height of 100% inside of the main div.
<div class="main" style="position: relative; width: 100%;">
<img src="your_image.png" style="width: 100%;">
<div style="position: absolute; width: 100%; height: 100%; display: flex...">
YOUR CONTENT
</div>
</div>
May be this can help, it's not exactly a background, but you get the simple idea
<style>
div {
float: left;
position: relative;
}
div img {
position: relative;
}
div div {
position: absolute;
top:0;
left:0;
}
</style>
<div>
<img src="http://www.planwallpaper.com/static/images/recycled_texture_background_by_sandeep_m-d6aeau9_PZ9chud.jpg" />
<div>Hello</div>
</div>
You can do something like that
<div style="background-image: url(http://your-image.jpg); position:relative;">
<img src="http://your-image.jpg" style="opacity: 0;" />
<div style="position: absolute;top: 0;width: 100%;height: 100%;">my content goes here</div>
</div>
If you know the ratio of the image at build time, want the height based off of the window height and you're ok targeting modern browsers (IE9+), then you can use viewport units for this:
.width-ratio-of-height {
overflow-x: scroll;
height: 100vh;
width: 500vh; /* width here is 5x height */
background-image: url("http://placehold.it/5000x1000");
background-size: cover;
}
Not quite what the OP was asking, but probably a good fit for a lot of those viewing this question, so wanted to give another option here.
Fiddle: https://jsfiddle.net/6Lkzdnge/
Suppose you have some thing like this:
<div class="content">
... // inner HTML
</div>
and you want add a background to it, but you do not know the dimension of the image.
I had a similar problem, and I solved it by using grid:
HTML
<div class="outer">
<div class="content">
... // inner HTML
</div>
<img class="background" />
</div>
CSS
.outer{
display: grid;
grid-template: auto / auto;
// or you can assign a name for this block
}
.content{
grid-area: 1 / 1 / 2 / 2;
z-index: 2;
}
.background{
grid-area: 1 / 1 / 2 / 2;
z-index: 1;
}
z-index is just for placing image actually at the background, you can of course place img.background above the div.content.
NOTE: it might cause the div.content has same height of the picture, so if div.content have any children that placed according to its height, you might want set a number not something like 'auto'.
inspired by the most liked answer, I ended up coming up with a solution using min-height and 'vw' unit
I had an image in a very unusual proportion
through experimentation I ended up using
min-height: 36vw;
that value must change, according to the ratio of your image
css code used im my actual page:
background:url('your-background-image-adress') center center no-repeat;
background-size: 100%;
background-position: top center;
margin-top: 50px;
width: 100%;
min-height: 36vw;
code pen example https://codepen.io/viniciusrad/pen/GRNPXoL
Had this issue with the Umbraco CMS and in this scenario you can add the image to the div using something like this for the 'style' attribute of the div:
style="background: url('#(image.mediaItem.Image.umbracoFile)') no-repeat scroll 0 0 transparent; height: #(image.mediaItem.Image.umbracoHeight)px"
I have been dealing with this issue for a while and decided to write a jquery plugin to solve this problem.
This plugin will find all the elements with class "show-bg" (or you can pass it your own selector) and calculate their background image dimensions.
all you have to do is include this code, mark the desired elements with class="show
Enjoy!
https://bitbucket.org/tomeralmog/jquery.heightfrombg
The best solution i can think of is by specifying your width and height in percent . This will allow you to rezise your screen based on your monitor size. its more of responsive layout..
For an instance.
you have
<br/>
<div> . //This you set the width percent to %100
<div> //This you set the width percent to any amount . if you put it by 50% , it will be half
</div>
</div>
This is the best option if you would want a responsive layout, i wouldnt recommend float , in certain cases float is okay to use. but in most cases , we avoid using float as it will affect a quite of number of things when you are doing cross-browser testing.
Hope this helps :)
actually it's quite easy when you know how to do it:
<section data-speed='.618' data-type='background' style='background: url(someUrl)
top center no-repeat fixed; width: 100%; height: 40vw;'>
<div style='width: 100%; height: 40vw;'>
</div>
</section>
the trick is just to set the enclosed div just as a normal div with dimensional values same as the background dimensional values (in this example, 100% and 40vw).
I solved this using jQuery. Until new CSS rules allow for this type of behavior natively I find it is the best way to do it.
Setup your divs
Below you have your div that you want the background to appear on ("hero") and then the inner content/text you want to overlay on top of your background image ("inner"). You can (and should) move the inline styles to your hero class. I left them here so it's quick and easy to see what styles are applied to it.
<div class="hero" style="background-image: url('your-image.png'); background-size: 100%; background-repeat: no-repeat; width: 100%;">
<div class="inner">overlay content</div>
</div>
Calculate image aspect ratio
Next calculate your aspect ratio for your image by dividing the height of your image by the width. For example, if your image height is 660 and your width is 1280 your aspect ratio is 0.5156.
Setup a jQuery window resize event to adjust height
Finally, add a jQuery event listener for window resize and then calculate your hero div's height based off of the aspect ratio and update it. This solution typically leaves an extra pixel at the bottom due to imperfect calculations using the aspect ratio so we add a -1 to the resulting size.
$(window).on("resize", function ()
{
var aspect_ratio = .5156; /* or whatever yours is */
var new_hero_height = ($(window).width()*aspect_ratio) - 1;
$(".hero").height(new_hero_height);
}
Ensure it works on page load
You should perform the resize call above when the page loads to have the image sizes calculated at the outset. If you don't, then the hero div won't adjust until you resize the window. I setup a separate function to do the resize adjustments. Here's the full code I use.
function updateHeroDiv()
{
var aspect_ratio = .5156; /* or whatever yours is */
var new_hero_height = ($(window).width()*aspect_ratio) - 1;
$(".hero").height(new_hero_height);
}
$(document).ready(function()
{
// calls the function on page load
updateHeroDiv();
// calls the function on window resize
$(window).on("resize", function ()
{
updateHeroDiv();
}
});
If you can make an image on Photoshop where the main layer has an opacity of 1 or so and is basically transparent, put that img in the div and then make the real picture the background image. THEN set the opacity of the img to 1 and add the size dimensions you want.
That picture is done that way, and you can't even drag the invisible image off the page which is cool.
just add to div
style="overflow:hidden;"

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