From Slack conversation with @lannka and @powerivq:

"Ads never generate these things (srcset/sizes) on ssr'ed img tag."

Hi all! Sorry for delay. I was OOO. If I'm reading this right, this will disable sizes generation in cached pages. Not sure if that's what you were going for? If we want to do this, IMHO, we might as well remove the concept sizes-generation entirely from the amp-img.

If I'm reading this right, this will disable sizes generation in cached pages.

This will only disable automatic sizes generation.

In general: agree with removing the concept, if we can prove its non-breaking.

In general: agree with removing the concept, if we can prove its non-breaking.

To confirm: this PR does just that - disables automatic sizes generation for cached pages. Is that right?

It removes the auto-generation for images with the attribute i-amphtml-ssr.

I am quite nervous about the backward compatibility, asked here: https://github.com/ampproject/amphtml/pull/32647/files#r575565890.

There's pretty much my question as well. The i-amphtml-ssr, I think, will be produced for most of amp-img tags on cache.

Afaik it'll only be generated for server-side generated img elements, which currently only happens for ads and in AMP Optimizer. AMP caches only render the layout, but not the actual img element and don't set the I-amphtml-ssr flag.

/cc @jridgewell to confirm in which cases we render img and i-amphtml-ssr.