The copyright status of pictures is one of the most intractible problems on the web and this post from Wired offers what could be a sensible solution: add a tag in (X)HTML:
Currently there are eleven attributes for the img tag, two required and nine optional. Frankly the tag is already bloated enough that I don’t think one more attribute is going to matter. Something as simple as
lic="license-abbr"would do wonders for image rights on the web.