Image width specification in html5

[David Swindlehurst]

Hi folks:

The W3C Validator for html5 (as with previous versions) accepts element 
widths specified in percentages, through CSS, which enables accurate 
page rendering for any size of display. EXCEPT that it refuses to accept 
percentages for specifying width for the img tag! For instance

<div class="?"><img src="image.png" alt="ancient grey-haired awkward 
person" width="25%" /></div>

results in an error - the Validator expects an absolute number (of 
pixels!). Fixing image width like this prevents correct rendering of the 
page in any size of display different from the writer's original. 
Although there is a mass of insignificant discussion in the current 
Specification about the "alt" tag, there is no mention of image sizing 
at all, which seems to me to be far more important. Does the Spec need 
revising, or is the Validator wrong in expecting an absolute number?

DMS