Flames - layered blue

Jeff...great flames! I did a Google search looking for some flames for a design project that I am working on and came across yours and the Deviantart site. I shoot alot of hot rods and other types of vehicles so I signed up. I don't really understand how this works but if I wnat to use some of your flames for backgrounds do you sell them or do I give you a credit? Please let me know.
Thanks,
Paul
elhotrod34@yahoo.com