Article Update: Don’t Rely on Default `sizes`
Too many people were relying on the invisible default for images whose display size wasn’t even close to 100vw, resulting in inappropriate srcset selections and wasted bytes. Developers learning the new markup were also getting tripped up on how sizesaffects intrinsic sizing.
Sizes are no longer optional when using srcset and w descriptors and won’t validate based on the spec. Eric Portis explains why that’s the case.
An excerpt from Article Update: Don’t Rely on Default `sizes`
