I've been doing some more sniffing around on the 'Net for a work project, and I've come across this very nice project: The Rode Project, featuring two altars by the late-medieval artist Hermen Rode. One of them is in Lübeck, the other in Tallinn, and both are absolutely spectacular - and you can have a really close look at them in the Rode Project.

Both are from the late 15th century, and you can virtually open them to enjoy the altars in all their aspects - plus see the paintings in infra-red or in normal light. And, of course, marvel at the wonderful things that all the people are wearing!