This site is a bit obscure (medieval Tibetan and all that) but has some images on Buddhism, Tibet, China and the Silk Road. It's from a site at Dunhuang, which is along the old Silk Road.
This exhibit was organized as part of Silk Road Seattle, a collaborative public education project
exploring cultural interaction across Eurasia from the first century BCE to the
sixteenth century CE.
While this site has items for sale, the "Multimedia Resources" tab under "Resources" has many FREE interactive online resources! Interactive maps and websites, videos and games!
A vast and unorganised collection of secondary and primary source sites on all things Mongol. Amazing that there are so many sources left seeings the Mongols tended to burn any sources they came across. Along with the people who might have written them, come to think of it. Maybe that's why their PR is so bad?