Bugzilla

Using `about:debugging` to do similar investigation to what I did in comment 3 but with today's Facebook design, I confirmed that Chrome is still getting a higher-res image than Firefox.

My `window.devicePixelRatio` on this device is `2.727272727272727`, so for ideal crispness, we'd like an image whose native size is ~2.75x the size that it's displayed on-screen.

In Chrome, that is indeed what happens -- they receive a 99px by 99px image file, which gets painted to a 36px by 36px area. (which is a 2.75x scale factor).

vs. in Firefox Nightly, we receive a 34px by 34px image file, which gets painted to a 34px by 34px area.

So, Facebook doesn't seem to be accounting for the fact that we have a HiDPI screen here (which ideally should make them serve higher-res images, like they do to Chrome).

Using `about:debugging` to do similar investigation to what I did in comment 3 but with today's Facebook design, I confirmed that Chrome is still getting a higher-res image than Firefox.

My `window.devicePixelRatio` on this device is `2.75` in Chrome (slightly-different in Firefox for some reason -- `2.727272727272727`).   So for ideal crispness, we'd like an image whose native size is ~2.7x-3x the size that it's displayed on-screen.

In Chrome, that is indeed what happens -- they receive a 99px by 99px image file, which gets painted to a 36px by 36px area. (which is a 2.75x scale factor).

vs. in Firefox Nightly, we receive a 34px by 34px image file, which gets painted to a 34px by 34px area.

So, Facebook doesn't seem to be accounting for the fact that we have a HiDPI screen here (which ideally should make them serve higher-res images, like they do to Chrome).