I've trying to get into a new niche of promoting a new site that I made(in signature) or free public domain photos. Unlike many public domain photos sites, all these photos are taken personally by me so I have all authority to distribute them.
I am looking for places to submit my photos that give the authors credit for their work. So far, I'm submitting to flikr, wiki commons, and publicdomainpictures.net . Does anyone know other popular places I can submit to?

I basically trying to build something like pdphoto.org eventually.