Alicia, I tried Gimp and it is just what I needed! I downloaded Gimp a long time ago, but didn't know how to use it. I figured it out tonight and it gave me more flexibility with color adjustment. The program I was using that is on my computer would change the color of the whole picture, so background and everything, but gimp lets me change the colors that are in the jewelry. It isn't perfect, but I was able to get the colors a lot closer to what they are in person. Close enough now that I can list my necklace, so thanks!
Pat, I don't think my camera has a white balance adjustment. It has brightness, vivid, and warm and cool adjustments which I use. I was photographing an agate pendant that has a spring green base with turquoise bands running through it. My camera seems to have blended the green and turquoise and made a bright aqua color that almost glows, and has lost most of the detail of the agate. Gimp helped a lot though. I will look harder on my camera for a white balance adjustment though because it would be nice to get more accurate colors from the start. My camera also has trouble with some purples.
Paula, I tried to download PhotoScape, but it seems to have downloaded a bunch of unwanted programs (that I was able to uninstall), but I couldn't find PhotoScape on my computer.
Lorraine, thank you for the happy sales dust!
Robin, I think that will be what I do eventually, buy a used dslr.