Niv, 

Thanks for the pointers. 

http://wiki.creativecommons.org/Embedded_Metadata deals with embedding the licensing info directly in the resource file. It does not deal with semantically expressing this relationship in HTML. 

Meaning, given a resource file that does not include embedded copyright info, and a licensing entity that requires you to add a copyright acknowledgement next to the image, there is no way (that I know of) to mark the relationship between the copyright message and the licensed resource semantically. 

http://wiki.creativecommons.org/Developer leads to http://wiki.creativecommons.org/HTML which provides an example for specifying that a specific resource (MP3 in this case) is licensed and how:

However, the example (a screenshot) is linked to a resource that does not actually contain this example. 

So, still no solution.