Fluid Images in a Variable Proportion Layout

It is quite easy to process fluid images in independent layouts these days. However, for more complex interfaces, we often need to place images inside responsive elements, such as this card:

Assume this image is non-semantic content and is only used for decoration. This is great for using background-image . And, since this image contains objects, we cannot crop any part when responsively layout, so we choose background-size: contain .

The problem is: on mobile devices, this card orientation changes and becomes vertical, with the image at the top. We can do this using any type of CSS layout technology, and it is probably best to use a CSS grid or elastic box.

However, when we test smaller screens, we get the following results due to contain attribute:

This is not ideal. The image is resized to maintain its aspect ratio, and does not crop any details, and we cannot change background-size to cover if the image is important and should not be cropped.

At this point, our next attempt might be familiar: place the image inline, not the background.

On desktop devices, this works fine:

It's also good on mobile devices:

But on smaller screens, the proportion of the image will be distorted due to all fixed sizes.

We can spend hours adjusting images, cards, and elastic properties, adjusting back and forth. Or, we can...

Separate main content from background

This is the basis for gaining greater flexibility and flexibility in responsive images. While not possible in all cases, in many cases it can be achieved with just a little effort in design, especially if such an approach is planned in advance.

In our next iteration, we place the strawberry image on a transparent background and use CSS to set the blue color in the raster image. Continue to use viewport size in the demo by resizing the sample space!

Looking at the styles carefully, note that we also add padding to the div containing the image, so the strawberries don't get too close to the edges. We can completely control how close or far we want them to be with this padding.

Note that we also use negative margins to compensate for padding on external card wrapping, otherwise there will be blanks around the image.

Use object-fit attribute for inline images

Although the previous demonstration works, we can still improve this approach. So far, we assumed that the image was semantic-free content—but in this layout, image illustrations may also be more than just decoration.

If this is the case, we absolutely do not want the image to be cropped, as this is actually equivalent to data loss. To prevent this, it is best to place the image inline instead of the background, which we can do with object-fit property.

We have extracted the strawberry from the background, which is now an inline element, but we retain the background color in the same image div.

Finally, combining object-fit: contain with 100% width allows you to resize the window and maintain the aspect ratio of the strawberry. However, the downside of this approach is that we need to set a fixed height for the desktop version of the image—or else it will follow the proportion of the set width (reducing it will change the layout). If we need to generate these cards with a variable amount of text, the text will wrap, which can make things too restrictive.

Coming soon: aspect-ratio

The solution to the above problem may be soon implemented through the upcoming aspect-ratio property. This will allow setting a fixed scale of the element, for example:

 .el {
  aspect-ratio: 16 / 9;
}

This means we will be able to eliminate the fixed height and replace it with the aspect ratio we calculated. For example, the dimensions in the desktop breakpoint of our last example look like this:

 .image {
  /* ... */
  height: 184px;
  width: 318px;
}

Using aspect-ratio we can delete the height declaration and calculate to get the nearest 184 scale:

 .image {
  /* ... */
  width: 318px; /* reference width*/
  height: unset; /* Reset the height set outside media query*/
  aspect-ratio: 159 / 92; /* Close to 184px height*/
}

If you want to learn more, you can explore the upcoming attributes in this article.

Finally, there are multiple ways to achieve reliable responsive images in variable scale layouts. But the trick to make this work easier — and better — doesn't necessarily lie in CSS; it can be simple, just adjusting your image, whether it's to separate the foreground from the background (as we did), or choosing a specific image that still works even if a considerable portion of the edge is cropped.

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