I'm not an artist in the visual sense. I can imagine what my characters should look like. I can see scenery in my mind. I can play out a scene as if it were a movie. I can even relay these things to other people via the written word. But there's no way I can represent them via an illustration. A visual artist I am most certainly not.
While my desire to write came from reading, artwork has always been an inspiration as well. Fantastic artwork is part of what attracted me to, well, fantasy. The work of such luminaries as Boris Vallejo, Keith Parkinson (who unfortunately died of leukemia in 2005; he was always one of my favorites), Frank Frazetta, Larry Elmore, and others fed my imagination in ways mere words never could.
While I still look to those individuals for creative inspiration, the Internet has opened the field to a truly vast scale. Much like authors have been freed of the traditional publishing gatekeepers, anyone can upload a sketch or illustration to their blog, web site, or to one of the sites below. Quality varies as one would expect. But there's so much amazing artwork on these sites I wanted to share the ones I routinely check.
Keep in mind, of course, that content belongs to the creator unless you work out a license agreement. I do a lot of looking, but I never touch, so to speak. It's not OK to download and use someone's artwork without compensating them for it, same as writing. It's easy to work with most of these artists if you're interested in using one of their images for something. The illustration I use for the cover of The Hall of the Wood and as the header for this site was purchased from an artist on deviantart.com, for example, after I contacted him and we settled on a price. It was a win-win for both of us.
Here are the art sites I frequent. I know there are others. Please comment below with your own favorites.
1. Concept Ships
2. It's Art
3. Cool Vibe
4. Art of Fantasy
5. CG Hub
6. Ninja Crunch
7. Deviant Art
8. Creature Spot