Meta has related information at: Free image resources
Wikimedia Commons has media related to Commons:Free media resources.
The use of free content on Wikipedia:
- Wikipedia:Wikipedia is free content - an explanation of the third pillar of Wikipedia
- Wikipedia:Copyrights – Wikipedia policy about copyright issues
- Wikipedia:Public domain – guideline about how the public domain applies to Wikipedia
- Wikipedia:Adding open license text to Wikipedia - about how to use free content from other sources within Wikipedia
- Wikipedia:The Free Encyclopedia – essay about how copyleft is used to provide a collaboration framework for Wikipedia
- Wikipedia:WikiProject Images and Media/Free – Wikiproject with the aim of spreading the use of free images in Wikipedia