The Metropolitan Museum has made over 300,000 images available under the Creative Commons Zero (CC0) license.
Here is one I pulled out and put on Pablo in order to share with my fellow public domain sisters and brothers.
Solidarity with museums who share!
Here is the link to the collection.
And here is a link to a news item about the collection.
Permalink //
A person could spend a lot of time just browsing through on-line collections like this. Thanks for sharing the link.