Peek at: http://newcurrencyfrontiers.com/wagn/Sailing_off_the_edge_of_the_world
I've added +alt and +title tags to this image. Those should probably be a part of the standard image edit mode.
Ideally the wagn code would generate the HTML thusly <img src="[path]" alt="[+alt text] title="[+title text]" />
Frankly, you could have the alt and title tags default to the card name if there are no pluscards present for them. That'd be awesome!
I'm not quite sure how to deal with Creative Commons attributions... except to add something like +attribution card. It probably wouldn't render in the HTML (I suppose it could attribution="some text here" would probably just be ignored by the browser) but it would certainly be visible when somebody views that actual image card.