[Plugin: Custom Author Byline] Custom Byline for Media?

I use wordpress to power a publication whose contents have diferent authors. I love this plugin, for its ability to let me indicate the author of text, but is there any way to customize the byline for images/media?

I saw this: http://wordpress.org/extend/plugins/media-author/
But that plugin requires a user account for every author, which isn’t really ideal in my case.

Any ideas?

http://wordpress.org/extend/plugins/custom-author-byline/