Repairing Image Size Issues on my Website

I recently noticed that my website images were not displaying their sizes correctly when I turned off image-dimensions using Chris Pederick’s Web Developer Tool.

This piqued my curiosity, so I began researching to understand why this was happening. My search quickly led me down a rabbit hole into the web.dev articles, wherein I found this article providing valuable insights on optimizing Cumulative Layout Shift (CLS).

The following is my TL/DR about the information provided that is helping me update my website to both appear and load better:

Understanding Cumulative Layout Shift (CLS)

CLS is a key-metric in web-performance that measures visual stability . Unexpected layout shifts can be jarring for users and degrade the user experience. One common cause of CLS is images and videos without specified dimensions. When these elements load, they can cause sudden shifts in content, leading to a poor user experience.

Presetting Space Height for Images

To prevent such layout shifts, it’s crucial to include 'width' and 'height' attributes in your HTML for images and videos. This allows browsers to reserve the correct amount of space while these elements are loading.

Here’s an example:
html <img src="image.jpg" width="600" height="400">
By setting these attributes, the browser knows exactly how much space to allocate for the image, even before it fully loads. This ensures a smoother and more stable layout.

Using CSS for Responsive Images

For responsive designs, the 'aspect-ratio' CSS property can be highly effective. This property helps maintain the correct aspect ratio for images, ensuring that they scale properly without causing layout shifts.

Here’s how to use it:

<html>
<style>
 .image-container img {
 width: 100%;
 height: auto;
 aspect-ratio: attr(width) / attr(height);
 }
</style>
<div class="image-container">
 <img src="image1.jpg" width="800" height="600">
 <img src="image2.jpg" width="1200" height="800">
</div>

In this setup, each image within the 'image-container' class will maintain its aspect ratio based on the 'width' and 'height' attributes specified in the HTML. This approach ensures that images remain responsive while preventing any unexpected layout shifts.

Ensuring Layout Stability

Beyond images, other elements like ads, embeds, and iframes can also cause layout shifts if not handled properly. It’s important to reserve space for these elements and manage animations in a way that doesn’t trigger re-layouts. For example, animations should use transform properties instead of properties that force re-layouts, again, like 'width' and 'height'.

Conclusion

Optimizing CLS is crucial for maintaining a stable and user-friendly web experience. By setting dimensions for images and using properties like 'aspect-ratio', you can prevent layout shifts and improve the overall performance of your website. For more detailed information, you can refer to the full article on web.dev .

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