I don't have the time to write example code right now, but you'll need to know to use a Loader to get your pics once you have the urls. You may run into trouble with crossdomain.xml, so if you do you'll need to have a crossdomain.xml policy at www.domain.com/crossdomain.xml which gives permission to www.my.domain.com to use assets.

Other than that, any number of xml gallery tutorials should point you in the right direction.