I've added a couple properties to the library images (Description, LinkToURL) and I'm able to read them in a custom control. Simple, but good stuff. What I want to do is have the property for LinkToURL (in edit mode) open a div with the site tree to allow users to select the page and store that page in the property. I suppose it might make even more sense to use the GUID for the page (or whatever you use internally) so that chaning the location of the page in the sitemap won't break the link.
Currently users just navigate to the page and copy/paste in the URL and remove the domain information (as we have a different environment for test and production).
I started looking at the UrlPicker tree control and was making a little headway, but figured I should ask before going too far down a road that might work but not be the most effective way of doing it. Is anyone doing something similar to this?