Trying to find a good affiliate/blogroll plugin

I don’t know if “affiliate” or “blogroll” is exactly the right word here, but I want to find a plugin that allows me to add “affiliate sites” that are essentially sites related to the same topic as me, where we each have agreed to promote each others’ sites for one another, through use of a small image, like a button or a banner.

It’s basically the old Blogroll function, except with images instead of plain text links, and I could add a widget onto an existing page or part of the site so it always shows up.

Does such a plugin exist, or do I even need a plugin for this task?