I have an image that I use many times. In several cases I want to shrink its size, but obviously it loses sharpness when I do this in HTML.
Is there a way to fix this? The image is located elsewhere and I can’t save it locally.
Thanks
As dheerosaur states, SVG graphics can be used when you need to have the same image in multiple sizes but don't want to compromise quality.
Another thing to do is use an online service, such as Resize.co. You pass them the URL for your image file, the attributes and they take care of everything else.
You cannot control the way the browser renders images when they are resized. Images will look better when being passed through Photoshop's filters (or those in another tool) upon resize.
There is three way that I know to reduce an image file size in bytes :
Convert the file into a format using lossy compression algorithm such as JPG. Obviously the image will lose sharpness
Convert the file into a format using lossless compression algorithm, like PNG. Only works if the image contains lots of region with flat colors
Resize/resample the image using Photoshop or GIMP. If the new image dimension (width x height) is exactly the same as the displayed image's dimension in HTML, then web users will still see a sharp image
Firefox and Internet Explorer actually do have CSS properties that adjust the way images are rendered when resized via HTML attributes or CSS properties:
Firefox: image-rendering
Internet Explorer: -ms-interpolation-mode
These won’t work in other browsers, and may not work great in all (or any) versions of IE and Firefox.
But it might be worth experimenting with them as a fallback in case resizer.co causes any issues.
Related
TL;DR: Is it possible to load other images based on media-query from svg included via img tag?
I generate a bunch of svg files with have tables with text and icons inside. A PDF would be semantically a better container, but I need to keep such "documents" as images for seamless embed/preview and it probably won't solve my problem. So the story is about icons.
I wrote inline styles with media queries picking icons corresponding to user's screen DPI. Icons are already bundled into sprites, so I use pattern/image[xlink:href] + fill:url(#id). Everything works as needed when I embed svg directly into HTML (DOM islands). But if I embed svg via img tag (i.e. <img src="foo.svg">), it doesn't load icons at all, let alone showing them.
I understand, that I can embed icons via data-URL, but embedding icons for all supported screen dpis seems too much. The irony is that icons are raster ones, hardly vectorizable pixel-art, so I cannot have one set of icons for all DPIs.
Is there a way to have proper icons picked by media query w/o embedding them all?
You can't load external files from an SVG used in an <img> tag (or used in other "image" contexts, like CSS background images). For security and performance reasons, SVG used as image has to behave like any other image -- a single file, no secondary resources and no scripts.
If you don't want to use inline SVG, you might consider embedding an SVG file with an <object> tag or <iframe>. However, I recommend that you actually test carefully to see whether browsers are downloading the image files even if they aren't using them because of CSS.
So since it's not possible to load conditionally: either embed or not, I should do some clever detection about raster sets. Technically not a direct answer, but in case someone needs.
I decided to go with cookies. People visit normally the same site that hosts those SVG.
I'd set a cookie for their DPI and then all SVGs served would pick proper DPI images.
For people who haven't visited the site yet, I'd go with UA sniffing: mobiles and macs get 2x, others 1x. Or just 1x for everyone.
I'm really confused with this one as it seems impossible to do.
When running my site through GTMetrix I pass great but with Google page speed insights it's insisting my images can be optimized more for instance:
Compressing and resizing mysite.com/…ets/img/homepage/my_image.jpg could save 78.5KiB (94% reduction).
The image in question is 65KiB so how Google thinks I can shave another 78.5 off it I don't know.
I'm using jquery unveil and using the retina function on it too could that be the problem?
Also I've tried downloading the images Google provides as their compressed version but these images have had their dimensions changed so would look terrible if I put them at their intended size.
Really confused, any help would be appreciated.
Thanks
There are few things you need to distinguish before proceeding with optimizing images for Google Page Speed.
Images are optimized for different platforms (Desktop and Mobile)
Images are optimized for physical size.
Reports for images can be "Compressing and resizing" and "Compressing" only. Compressing means u need to do a compression part, on other hand compressing and resizing means you need to use appropriately sized image for appropriate platform.
Depending on the report you are looking at (desktop or mobile), your item "Compressing and resizing mysite.com/…ets/img/homepage/my_image.jpg could save 78.5KiB (94% reduction)." needs to be less in dimensions and compressed or just less in dimensions. Margin for resizing an image with CSS is around 20% so if you got 100x100px image you can resize it to around 120x120px with CSS without getting report on that item (that is if you also optimized it physically also). To check this in Chrome, inspect image and check "Natural" size in element selector.
You can deal with this on few ways:
Media Query (note that you have to use background image in this case)
Srssets
JS
Depending on the image compression package that you use, you might get different compression results. I've noticed that sometimes Google's Page Speed is able to optimise an image further than I have been able to (and other times not!)
Do you have a live URL for your web page? Or even the image? It helps to be able to see it live and compare!
If an image is 200px by 200px and you give that image a class in css with the same dimensions, will the browser still resize that image via css?
Ive been looking frequently into reducing page load time and one of the things that comes up is resizing via css slowing down page load time.
If you apply a class to your image with some fixed dimensions, then it will stuck to the defined dimensions.
Unless you define "max/min-width" and "max/min-height" instead of width and height.
The loading time is not about the dimension of the image but more about the size (octets) of the file (here an image). The performance are poorly influenced by the dimension of it.
No, because image will be same size (as downloaded from server). Also, since width/height of class is same as image, image will not be resized. And I don't think that resizing such images has any impact on page load times.
We can resize image propertionally from css but can't reduce load time from css
Full optimization of images can be quite an art to perfect as there are such a wide variety of images you might be dealing with. Here are the most common ways to optimize your images for the web.
Use proper file formats. If you have icons, bullets or any graphics that don't have too many colours use a format such as GIF and save the file with lower amounts of colours. If you have more detailed graphics then use JPG file format to save your images and reduce the quality.
Save your images in the proper dimensions. If you are having to use HTML or CSS to resize your images, stop right there. Save the image in the desired size to reduce the file size.
To resize your images you will have to use some form of program. For basic compression you can use a simple editing program such as GIMP. For more advanced optimization you will have to save specific files in Photoshop, Illustrator or Fireworks.
Source Link
Edit:
Check this link to get more idea about speeding up page loading time
Is there a method to include CSS background images in print?
If i use image replace techniques for (which is considered as a best practice) Logo then logo doesn't come in print.
and many places in site CSS background is saving bandwidth and my time both. but client is asking to include many things in print also.
And many places where i used background images but now client need background too at some places but on some places not.
What should i do?
Can we do anything with print css?
None of the browsers I'm aware of print backgrounds by default (to save ink/toner). I would also suggest that this is a time when using an image replacement technique is a little overkill -- for a logo the image could appear in the document (and with the relevant alternate text, still accessible)
Is the only benefit of using css image sprites that there is less http requests?
Or is there other benefits?
Also is there an easy way of detiming which area of a sprite to show?
Like you said, one of the main advantage is to reduce the number of requests to the server, improving the response time (especially if you're loading a large amount of small images). But this is not the only reasons people use sprites.
If you don't use sprites for a "mouse over" display, the user will see the image disappear for a second... and it looks really bad. This is because if you change the image instead of just moving the sprite around it will load a new image and the loading time can be visible to the end user.
.bad{
background:url(abc.jpg);
}
.bad:hover{
background:url(abcHover.jpg);
}
.good{
background:url(abc.jpg) 0px 0px;
}
.good:hover{
background-position:15px 0px;
}
Another advantage of sprites is that you can keep all your images in one location and in some cases it makes more sense (for menus and so on).
To determine which area of a sprite to show, just use photoshop or any other image editing software.
The primary benefit is your pages load faster, mainly because of reduced HTTP requests.
You could generate your sprite using a tool.
Disclaimer - I wrote this tool.
It is much easier to get image placement (especially next to text) the same cross-browser. You can adjust images up/down/left/right with out using vertical-align and padding.
I find it easier to keep track of all the images if they are in a single file. Especially since I usually have a transparent png images and and then use gif images for ie6. I save my png sprite map as a gif and add one line with background-image in my ie6 css and my images are switched.
I use photoshop or gimp to get approximate locations in the sprite map and then use firefox to fine-tune the placement.
Yes, there is another benefit. Every image file has his own headers, describing image type, colors etc. So when you combine images to a single sprite, you win some kb.
But as you said before, mostly you win by reducing HTTP requests count.
In terms of determining the area to show, I will typically place my elements on pixels that are multiples of 100. So if there's a sprite with a bunch of 64x64 pixel icons, I'll typically have them at (0, 100), (0, 200), (0, 300), etc.
This way, I don't have to type in an exact measurement (or any other developer for that matter) and save keystrokes when setting all my background-position properties.