Something Useful from the European Union...

-- Well, sort of... it's in beta at present but the European Union is assembling a huge online digital resource, which includes imagery from publishers as well as museums at: www.europeana. eu/portal

You can search for subjects etc and results are broken down into all results, text, images, video etc.

I did a quick search for comics and cartoons and got some interesting results, although some are postage stamp size so not much use. However, it does include imagery from the British Museum, for example, and I'm sure it will grow in its usefulness as organisations get their act together. DC Thomson, publishers of The Beano etc. are among the first on board, although there don't appear to be any of their comic strips available through this service just yet.