Public Domain for Artists
Whether you are a painter, photographer, or graphic artist/designer, public domain will certainly be something you hear about. Along with the knowing about and using the Creative Commons, here is a great resource for artists:
Wikipedia Image Resources*
This particular Wikipedia page provides readers with links to images and graphics which may be used be freely. It also includes a list of subject-based image resources, with subjects such as art, history, and literature. Use these images wisely, and always check to ensure you are not violating anyone’s copyright.
* Please note that before using some of these images, you must still check the copyright, using the knowledge you have gained from reading about public domain and proper search techniques.
Artist's Copyright FAQ: What is in the Public Domain?
About.com is a useful resource for quick answers to pressing questions, created by guides who, though not usually scholars or academics, have plenty of experience in the field discussed. Here is a short answer regarding when a painting, or any other work, might be considered public domain. Additionally, there is a link to a more in-depth FAQ on Artist's Copyright, as well as some potentially related articles near the bottom of the page.