I’ve got a project I’m working on and it’s been a real bear trying to find specific images of genuine Native American artifacts online. Items are mislabeled, unattributed, etc. I just found that the Smithsonian has a tool that lets you search their Native American Museum catalog by specific criteria such as material, location, technique, etc. Want to only see northeastern ethnographic items that utilize turtle feet? You can search for it.
http://www.nmai.si.edu/searchcollections/peoplescultures.aspxHopefully some of you will find this as useful as I have.