Will iPhoto suit my needs?

[udontno]

I'm doing some searching now (I'm always the idiot that forgets to search) and looking into watermarking.

 

[cdcastillo]

It seems you are already using iPhoto. I was going to suggest you use iPhoto for organization and light editing, and latter, if it doesn't fulfills your editing needs, you can complement it with Photoshop Elements. (Mac AppStore link)

I see someone has already told you about how to use iPhoto with the External HD. Good luck.