I just came across this website. It looks like a great resource for issues of racism and stereotyping. Not only are there tons of useful images, but the accompanying essays are solid too.
Authentic History Center
Stereotypes of Native Americans: Essays & Images
Native Americans in Comic Books
Rob says: Check it out. If you're like me, you'll spend an hour or two exploring it.
P.S. I'd post some of the images, but the owner has slapped a copyright statement on each one. Hmm. I'm not a lawyer, but I'm guessing that if you scan an image and post it with a © symbol, that doesn't give you ownership of the image. I'm guessing the original publisher or creator still owns the copyright.