Europeana aims to gather and digitized the collections of some of Europe’s largest libraries, archives, and museums.  Their website is still in beta; however, the collection is already quite extensive.

http://www.europeana.eu/portal/

It’s well worth the time to do some quick searches to see what resources are available. The images are not of the same quality that you would find in our Artstor subscription (http://library.artstor.org/library/welcome.html), though the collection itself is larger and includes audio and video as well.

Other sources you may be interested in:

• Flickr (Photo sharing site.  Most images in creative commons.  High quality photos, everyday life)
• ccMixter (Repository for music, most of which is generously licensed under a Creative Commons. Great for Podcast intro music etc.)
• Creative Commons Search (Search several popular web resources for creative commons resources)
• Blip TV (similar to YouTube, but much smaller and higher quality video)