I am noticing that webp images are becoming more popular and these sites are not being checked to see that the images are visible on all current browsers.
https://icons8.com is a good example of a very visual site with webp images. My macOS Catalina Safari 15.1 doesn’t display webp images, making the site useless to me. In the pursuit of either using newer imnage formats or a desire to reduce file size (or both) the web site completely fails.
I think that Google PageSpeed Insights is partially to blame here because it has in teh past flagged up jpeg and pmg images as areas to improve by using webp images.
Currently PageSpeed responds with:
" Serve images in next-gen formats
Image formats like WebP and AVIF often provide better compression than PNG or JPEG, which means faster downloads and less data consumption. "
On rechecking PageSpeed again today, I notice that this is now part of what Google call an “Opportunity” which appears before “Diagnostics”.