Model Design question in Rails

I have a site which has both articles and photos embedded in each
article. I want to allow people to comment on both a particular
article itself as well as on an individual photo in an article.

My questions is: What's the best design for the DB model - one
Comments table with a flag to say if the comment was on an article or
a photo or two separate tables - one for comments on articles and the
other for comments on articles? What's a good naming convention for
these tables?

I realize there may be no single correct answer but I am hoping to get
some good suggestions/ideas.

I'll correct some spellos first
1. My question is...
2. One for comments on articles and the other for comments on photos.

Have you looked into polymorphic associations?

Fred