See my comment above, you might understand it. I don't bother with source sets for different resolutions and file types, I just assume Retina and always serve a

See my comment above, you might understand it. I don't bother with source sets for different resolutions and file types, I just assume Retina and always serve a well optimised webp from a different cookieless domain. I did try AVIF but I have 60% iOS and those iPhones don't read AVIF, or didn't until last time I checked. Like yourself I was struggling away with the compile but then I wondered why I was bothering when I had something good already. For VIPS I use PHP. My index.php expects params of width and height in a query string. This sits behind an Nginx proxy that caches based on query string and accept headers. This is the origin server for a CDN that respects the headers. I am glad to see you are doing the colour profiles as sRGB as I do that too. Look into the trick of serving webp when another format is requested, it works great. You can then simplify the HTML and use picture elements for more fun things such as responsive things.