Comment 4 for bug 1531913

Specifying a blank artwork is still possible, and still not sensible. One can always specify a 1x1 transparent image as the artwork for intentionally blank space. :)

We don't detect that we are sending an empty image. We just specify the fallback and expect it to work as a fallback should. If a fallback is not shown when no artwork is passed, then it's not a fallback. If it's the image to be shown when there is an error loading the image, then the API is wrong, because developers might want to show something else in case of error, so that it's known there was an error. Changing the scope to do the work would mean duplicating code and logic. Why should we have to specify the image that we want to fall back to, in two completely different ways, in the same code?