Responsive images
Responsive website design assumes using images that can adapt to different user devices and browsers. Uploadcare allows you to get the most appropriate image size and resolution to improve users’ accessibility and enhance your website’s performance.
Uploadcare’s on-the-fly CDN provides a comprehensive suite of image processing operations for crafting an optimal responsive image experience on your website. It automatically identifies the maximum compression level that maintains visual quality without noticeable artefacts. Additionally, it offers a robust set of image processing tools to resize, crop, and scale images to suit your requirements.
You can improve the display of responsive versions of an image using art direction.
When saving images to the Uploadcare CDN, you can access automatic intelligent conversion and compression through URL operations.
Auto format is automatically applied to this image.
For retina screens add -/quality/lightest/:
Adaptive quality is also automatically applied to this image if you enable in the Dashboard.
Automatically
You can use the adaptive image component tool to adjust responsive images automatically.
You can implement a script to deliver optimized images automatically to users. Image optimization occurs in real-time during user requests, with results cached on our CDN.
- Connect the Adaptive Delivery JS script
(ensure you use your own public API key)
instead of
YOUR_PUBLIC_KEY):
- If your images are hosted outside Uploadcare CDN, whitelist the image sources. Go to “Settings” → “Delivery” → “Allowed domains for Proxy” in the Dashboard, click “Add domain” and add the domains you intend to use.
- Replace your
imgtags withuc-imgtag:
Note: uc-img is not self closing tag, so you need to close it with </uc-img>.
You can further enhance your responsive, optimized, and lazy-loaded images by adding various filters and effects and selecting different delivery options. Check out adaptive image component for more details.
Next.js
You can optimize images by using the Next.js image loader and component.
Nuxt
You can optimize images by using the Nuxt.
Manually
You can configure responsiveness manually.
Make a single image responsive
To make a single image responsive without using JS:
- Resize the image to fit the widest container, ideally preserving its aspect ratio.
- Set width: 100%; declaration to the image block so that the image adapts to the container width automatically.
- For instance, if your original image resolution is 4928x3280px with
a file size of 1.85 MB:
If the container width is limited to 1200 px on the widest screens, use the resize operator in the image URL to reduce its resolution and file size:
Insert the updated image URL into the src attribute of the <img> tag:
The original image width has been reduced to 1200px, and the file size has been reduced to just 125 KB.
However, this 2400px wide image is hardly necessary for an iPhone version of the website, which needs only 320px width by a 2x pixel ratio, which gives us 640px. If you want to smartly adapt your images to various screen widths, continue to the next section.
Optimize the image for high pixel ratios
Set an additional version of the image for HiDPI screens with
the <img> element and the x descriptor.
Retina screens have a pixel ratio of 2. To optimize for them:
- Multiply the
resizevalue by 2. - Reduce the image quality using
the
qualityoperation. - Add the alternative image link to the
srcsetattribute followed by the2xdescriptor that ties the image to devices with a 2x pixel ratio.
Example with the same image on Uploadcare CDN to produce an alternative retina version of it:
Optimize an image for different screen widths and breakpoints
Use URL API to:
- Create various resized versions of the image for different screen widths.
- Add them to the
srcsetattribute followed by awdescriptor with screen width in pixels - Add the
sizesattribute to the<img>element to set primitive media conditions. It should contain information on how much of the viewport will be occupied by the image
Example from the previous section that now contains various versions
of an image optimized for many different widths in w descriptors.
Replace 36f90908-afb9-4e0a-b254-1b769faf8f3a with your image UUID:
In this example, this value of sizes tells the browser to set the
image width to 50vw if the viewport width is 1000px or more; otherwise,
occupy most of the screen width:
sizes="(min-width: 1200px) 50vw, 90vw"
Take a look at this to see our pal Greenpaws adapt to various screen sizes, and make sure to try some of your own pictures in it.
Art direction
The art direction issue involves wanting to change the image displayed to suit different image display sizes. For example, in a broader sense, apply filters, control colors, and so on, or a web page includes a large landscape shot with an object in the middle when viewed in a desktop browser. When viewed on a mobile browser, that same image is shrunk down, making the object in the image tiny and hard to see. It would probably be better to show an image on mobile, which zooms in on the object.
Scale instead of resizing example
Usually, your image looks the same in portrait versions of devices, on desktops, and in landscape versions. That may be fine for square images, but the subjects of the wide images will probably end up looking too small on mobiles:
Use automatic cropping of an image to an object using the
scale_crop operation
instead of resizing images and combining them with media queries.
To use the same image for different layouts — for example, a landscape image
showing the entire scene for a desktop layout and a portrait image showing
an enlarged main subject for a mobile layout — use the <picture> element.
Use srcset/sizes to create a resolution switcher example, serving the same-size
image at different resolutions depending on the device resolution or different
image sizes depending on the viewport widths.
Note: We recommend using the media attribute only in art direction scenarios.
If you use media, don’t also offer media conditions within the sizes attribute.
Enable art direction
Art direction is the focus of the main subject of the image. It is essential for smaller screens. On the large screen, we can show the entire image, but on a smaller screen, we want to show just the main part of the image.
We want to show only the chameleon’s head on smartphones:
Use the crop operation with the
resize operation to get a custom part of an
image. Use the <picture> element to implement an art direction picture switcher.
Use the crop operation to get the main part of an image and use
the resize operation after that.
If your image contains a face, it’s easy to use the
crop by object operation
without additional resizing.