Add support for width and height for Source Element

[alexander-schranz]

Not yet supported by all major browser but still validate for w3c validator:

https://caniuse.com/mdn-api_htmlsourceelement_width

<picture>
    <source srcset="test2.jpg" width="200" height="200">

    <img src="test.jpg" alt="hello" width="200" height="400">
</picture>

The question is should a width and height even written when it is the same aspect ratio as the original file as that would just bloat the html with unnecessary informations.

[FlorianBoe]

Width and Height attributes on the source element are now supported in all current browsers since Firefox 108.

[mario-fehr]

@alexander-schranz is this not fixed with #46 ?

[alexander-schranz]

sizes and width and height are different attributes on the <source> tag:

• https://developer.mozilla.org/en-US/docs/Web/HTML/Element/source#browser_compatibility

and width and height is not implemented yet.