Created attachment 221081 [details]
While testing srcset out on a 100x100px image with a 2x image, I discovered that in the nightlies, the 2x image is rendered 2x the width and height instead of the same width and height but with 2x density. A simple repro is attached.
The intrinsic size of the image should be adjusted based on the candidate's Nx value. This is clear in the WHATWG spec, but is not currently clear in the W3C one. (It will become clear when I next pull in the relevant WHATWG changes.)
*** This bug has been marked as a duplicate of bug 123832 ***