If you have a Site for free line arts that players can use, know of stock photo sites that are free use, or have other art guides, like Photoshop or Gimp Tutorials then add them here.
If you are not a PPGI mod, you can submit the links on the following thread:
http://www.virtualhorseranch.com/phpbb3/viewtopic.php?f=111&t=158996&start=0
Many thanks to Tala of Black Magick and Ride_to_live for the original threads that provided a portion of the links here.