Element `img` is missing required attribute `src`

[pdehaan]

Per https://html5.validator.nu/?doc=https%3A%2F%2Fmonitor.firefox.com&showimagereport=yes

Seeing 6 instances of the "Element img is missing required attribute src." error.

From line 49, column 13; to line 49, column 183

<img class='monitor-logo' srcset='/images/monitor-logo-transparent.webp 213w, /images/monitor-logo-transparent@2x.webp 425w' width='213' height='33' alt='Firefox Monitor'>↩     

Quoth the MDN:

Using src with an image set

When using a set of images with the srcset property, the src serves as either a fallback for older browsers, or as the 1× size of the image.
— https://developer.mozilla.org/en-US/docs/Web/API/HTMLImageElement/src#using_src_with_an_image_set

So it appears that the src is still required/recommended as a fallback when using srcset. 🤷

[pdehaan]

I'll call it related, but there's another 6× errors re: sizes attribute on the <img> tag:

When the srcset attribute has any image candidate string with a width descriptor, the sizes attribute must also be present.

From line 49, column 13; to line 49, column 183

<img class='monitor-logo' srcset='/images/monitor-logo-transparent.webp 213w, /images/monitor-logo-transparent@2x.webp 425w' width='213' height='33' alt='Firefox Monitor'>↩     

if you want to track this separately, we can convert the comment into a new issue (or do your Jira thing or whatever).