I just came across something that I believe worth commenting on here for others to see.
In HTML5, if you enter an image dimension as a percentage, it will not validate. The only reference I could find on the W3C site about image dimensions is this:
You will notice that it specifically states:
The dimension attributes are not intended to be used to stretch the image.
In some ways, that's fair enough but surely there are occassions where cross-platform image scaling may be appropriate? It was allowed in XHTML, so this seems to be a back-track on the part of the W3C.
Then again, there's a route out. CSS (at least CSS3 - not checked earlier versions) does allow percentage values for image dimensions.
So for anyone wanting to scale an image, ditch the HTML attribites and use CSS instead. Both HTML and CSS will validate.
Does this not render the clamp-down on HTML image scaling pointless?