<img>.complete should take <source> elements into account

[johannesodland]

The specification for <img>.complete disregards image sources from a <source> element.

Given the following example. (Assume that the lazy load resumption steps and Fetch the image haven't been invoked yet.)

<picture>
  <source srcset='image.jpg'>
  <img loading='lazy'>
</picture>

Per spec <img>.complete should be true as the first bullet applies. Both the src and the srcset attribute on the image are omitted.

This seems a bit off.

The selected source is set to the the url from the <source> element, and the image lazy load resumption steps is set to fetch the image from the selected source at a later point.

In the source there's a comment that seems to indicate that it was intended to check sources in the <picture> parent:

<!--TODO: check picture parent-->

Should the spec be updated to account for the selected source?

Strictly, yes, the src attribute must be present on the <img> element, same as the sizes attribute must be present if srcset is set. But when the src attribute is omitted by authors, returning true would still be unexpected if there's a current request for a selected source who's state is not completely available or broken.

[annevk]

We don't assign issues. You can open a PR when you have a fix.

[johannesodland]

This issue is related to #9181

If the src attribute is made optional, the getter steps for <img>.complete should be updated.