Some of the images that I am using are small icons. How can I scale them when viewing them at much higher resolutions such as 2560 x 1440?
Bojan is right: Using imulus.github.io/retinajs is a good way to accomplish this. A few things to note:
in your initial design, you should set your entire document to 150ppi. This is double resolution for retina display. When you're designing be sure all of the images and icons are scaleable to this size without pixelation.
Before you begin your build, cut out your images at this size and save them out like normal.Then scale it down to 72ppi so as you can cut out regular resolution images, and take measurements while you replicate the design into a website so you aren't constantly dividing by 2.
retinajs will replace your images as needed, but it will require you to assign dimensions to images that may not have them.
hope this helps
Related
I have a very large hero image, set as a background-image, that takes up the entire initial viewport size. I want to serve up multiple sizes based on device resolution for improved speed.
Media queries seem like the best approach, but I have some questions about implementing them:
Would it be better to use the width feature or device-width feature? I'm thinking the latter, because the width can change if a user resizes their browser, which could trigger a new background-image to load. With device-width, I can detect the largest possible screen size and load an image whose dimensions can look good if the user resizes their browser to full size.
How do you accommodate for pixel density? I need to make the images twice as big, or in some cases, three times as big, so they render properly on devices with large pixel density. So I can't really cut down the image size that much when I have to account for potentially high pixel density. I could make media queries targeting specific pixel densities and device-widths together, but that's seems like a complicated and suboptimal solution.
I'd love to hear some solutions people have found for this.
I am looking to make a website dynamically scale its assets (png/jpg) and output the appropriate css for three sets of resolutions: 540p, 720p, 1080p
Currently we have assets created for each resolution, so thats 3 sets maintained manually, ideally I want a Jenkins/hudson job to create the assets (by scaling from the highest resolution asset set, maybe use imagemagick commandline) and then generate CSS to make the resolution layout possible.
This is clearly not an old or unique problem, I am wondering what is the best approach to take for this?
The webpage is intended for low computing power embedded devices, which have limited capability, albeit HTML5 supporting. The solution has to be a server side creation of assets and CSS scaling as we cannot rely on the devices to be able to cope with much scaling.
Look forward to your thoughts and replies.
Cheers in advance.
Not a real solution, but rather a work-around which is working well and is easier to maintain:
Replace PNGs with SGVs. Take the highest resolution version and use something like http://vectormagic.com.
For JPGs take the highest resolution version, but compress it heavily and use something like ImageOptim. This works well for:
Browsers are nowadays very good at resizing higher resolution images to smaller ones.
Since the pixel density is so high if you are using the full size, the compression (artifacts) will be much less visible. And if your browser is scaling down, artifacts will be less visible because of the smoothing your browser applies.
File sizes will be bigger, but not much, since you can use a higher compression and it's getting more efficient with the image's size.
Reference: http://www.fngtps.com/2012/reasonable-ways-to-use-high-resolution-images-on-retina-displays/
I want all images for a mobile site to be 640px wide, based on iPhone screen size.
All images should be the full width of the screen when shown img { width: 100%; height: auto; }.
For the images that are smaller than 640px wide, is it better to use the above CSS to scale them up, or should I use Photoshop or something to scale the actual image up? Does it even make a difference?
So does scaling up an image using CSS result in a better or worse image quality than using something like Photoshop to increase the size?
Scaling images up doesn't go well for the quality of said images, you need to sort out your priorities on this one. You can work on those images and increase the quality and size of those images in Photoshop so you don't lose any quality when resizing, but this will increase page loads or you could lose some quality, but improve page loads with smaller but more crappy images.
If you really want to target each device (computer vs mobile) perfectly you can use javascript to switch out the images. This can be done really easily using http://foundation.zurb.com/docs/components/interchange.html or similar libraries.
If the images are graphics or icons I might suggest just making them svgs and using those instead as they are crisp at a greater range of resolutions. If you go with this option its best to make their sizes multiples of two.
I have an 40px by 20px image with 72 Pixels / Inch.
I would like to create a Retina display version.
What should I do? Double the size? Change the resolution?
And in which format should I save it? PNG? JPG? ...
I am using this image on a web site ...
In your image editor, double the size of your image to 80px by 40px.
In your markup set the width to 40 and height to 20.
<img src="example.png" width="40" height="20" />
You should save as png if you need transparency or the image is line art. Save photographs as jpg.
My answer is convert your image into SVG
Do you have Illustrator? If so save your image as SVG (and have a png as a fallback if you want).
<img src="images/logo.svg" alt="" />
<img src="images/logo.png" alt="" />
As long as you use Modernzr which can work to get svg friendly in most browsers.
You can see it here how it's done:
http://toddmotto.com/mastering-svg-use-for-a-retina-web-fallbacks-with-png-script/
Hope it helps :)
A retina display image (or high-density display image) is double the pixel size of a standard image - its scaling factor is 2.0. This means that yes, for your 40x20 pixel image, you will need to make an 80x40 pixel version (that is then displayed at double pixel density on screen). The format doesn't matter as much, both PNG and JPG will work fine (PNG will not degrade in quality with compression, but the file size will be larger than JPG).
However, the problem with high-density display images is that they take up more bandwidth, and are unnecessary for devices that don't have the high resolution or Retina displays. This means more data transferred over the network, inconveniencing mobile users and those with limited data transfer caps.
One solution is to use something like Retina.js. It's an open-source javascript client script that will automatically load the retina-sized image from your server and swap it in-place for the low-density version, if it exists. It follows Apple's standard for naming high-resolution images - #2x, so you can have HTML code like this:
<img src="/images/my_image.jpg" />
and the script will search your server also for /images/my_image#2x.jpg. If it exists, it will load it and swap it in-place without having to worry about messing with CSS.
Generally as of this writing there are two types of retina displays, hence you should create an image for each type.
For a 2× device, you would need to produce twice the logical pixels' width and height with a resolution of 144 pixels per inch (72 ppi ✕ 2).
For a 3× device, you would need three times the logical pixels with a resolution of 216 pixels per inch (72 ppi ✕ 3).
Examples of 2× devices are the MacBook Pro (released in 2012-2019) and most iPhone since the iPhone 4. Examples of 3×
devices are the iPhone 6 Plus, and the iPhone X. However the iPhone Xr is a 2× device.
Hence for your case you would need images in 80 px ✕ 40 px and 120 px ✕ 60 px for 2× and 3× devices respectively.
Retina displays are not dependent on the specific bitmap image format. You can use the original image format. For websites, you should use JPG for photographs and PNG for line-art graphics saved as bitmaps.
You should not just blindly enlarge images otherwise this would create a blurred results – it would no better than if you don't include any high-resolution versions in the first place. Either obtain the original higher-resolution version of the images (typically from vector graphic source) and downscale them or use a machine-learning based image enhancement solution such as Bigger Picture to "convert" your image into a higher resolution.
Photoshop gives you a couple options for resizing an image. For instance if the image is iPhone size you can increase the image size by 200%. Photoshop gives you a couple options for resampling of the image. Bicubic, bilinear and etc. This will remake the image at a higher resolution and interpolate the missing pixels. Hope this helps.
This is a really interesting article showing a nice option for dealing with high res images:
http://blog.netvlies.nl/design-interactie/retina-revolution/
Basically, it's saying that, if you make the image quite large (width and height) but then save it at quite low quality, it still comes out very sharp on retina displays. It means that you can use the one same image on all devices, and that the file size is very low, too, which is an extra bonus. You can set the width and height of the image in your CSS and/or HTML to set it to the visual dimensions you desire.
This article blew me away, and is my go-to approach for dealing with both retina-friendly and bandwidth-friendly images. Win, win.
You can use CSS opacity option.
This will give you an transparent look of your image based upon the value you set to opacity.
Try learning opacity: http://www.w3schools.com/css/css_image_transparency.asp
Does it matter how long and wide an image is when using CSS sprites? I noticed the SO sprite image is one long image, with all the sprites on top of each other.
Would having the sprites grouped together increase performance?
Due to png's filter/compression algorithm, large swaths of uniformly-colored pixels barely contribute to the file size.
The minor file-size cost of arranging your sprite vertically (like Stack Overflow), as opposed to squeezing your icons into a perfect square, is probably well worth the benefits of having cleaner CSS and a more maintainable sprite.
It would increase performance if you could reduce the image size. I doubt it would increase performance by much because reducing the image size will not reduce the amount of requests which is the whole reason for using sprites. That said, someone using dial-up might notice a difference.
Yes in few cases it would, because collectively many different images have a larger size than a single large images. Also the there will be no need for sending request for each image, all the required images will be available in a single sprite image. Then later your css will cut and use the required areas.
The difference will be noticed in low bandwidth connections where with multiple images each will be rendered with a little time gap, where as in a sprite based css, each will show almost simultaniously