To fakemonkey:
I used to be a professional graphic artist for a living. Now I just use those skills for my own sites.
You said,
"Most art I make is digital so it's not like I can sell the .jpeg"
One thing that is extremely important when it comes to digital art is, you need to know how to create in "vector" art format by using such applications as Adobe Illustrator or Xara Xtreme. By creating your work in vector art format, it allows the possibility of your images to later be scaled from the size of a postage stamp, all the way to being large enough to fit on a highway billboard without losing any image sharpness. PSD (Photshop) format is fine for web use, but if you hook up with a professional company, they will invariably want "AI" (Adobe Illustrator) renderings. Those can later easily be converted to PSD (Photoshop) images. But it is very important that your initial image is created in vector format.
You also need to know how to render images in CMYK (Cyan, Magegenta, Yellow, Kobol). That is for primt purposes.
It's nice to be able to create beautiful images with a computer, but in order to sell your images, you need to find out more about the tecnical aspects of what is demanded by companies who buy graphic work. Do some online research. There's lots of info out there.
I hope this at least helps to point you in the right direction. Good luck with your passion.
Cheers! - "Wiz"