Anyone know of something similar to Loupe that would allow my site to sign up users, have them register their flickr (or whichever image hosting site's) username/user id and pull images from that site?

Loupe looks sweet (and there are other similar apps) but it (they) seem to be geared for pulling one user's images over for a gallery on a personal site.

Anyone know if I can expand that to n registered users rather than a hard-coded one user?