Optimised images defined using srcset and parameters not used in tests

[pmeenan]

Well, that explains it. Must be server-side rendered react or something like that. Unfortunately that gives you the worst of both worlds. The browser will download and render the images defined in the HTML and then when the page is "hydrated" (the Javascript runs), it swaps out the images for the picture elements and....wait for it... the browser then ALOS downloads the webp images.

You can see this happen around request 42 in the waterfall where the webp versions of the images are downloaded: https://www.webpagetest.org/result/20081...view_step1