I'm trying to figure out how to make clip art out of my watercolor drawings. For example, I have a watercolor drawing of a pumpkin scanned onto my computer, and I need to know how to make the paper that is included in the scan transparent, so that I can use just the pumpkin image for designing cards, posters, calendars, etc. I want to make it into clip art. I know that Photoshop can do this, and probably Illustrator as well, but I want to know if GIMP or Photoshop Elements or any other program can also do this. Thank you so much!
This is a difficult question to answer, because without seeing the image, I just have to guess what you really want.
Clip art doesn't usually need to have a transparent background - most just have a plain white background. Is the existing background not white? If so then you could just paint it white. You can use the Paint Brush tool in both GIMP and Photoshop.
Are you planning to put the clip art onto a non-white background? Then you could create a layer mask in Photoshop or GIMP - both have that capability, or you could simply use the eraser tool on the background. You could export the resulting image as a PNG, which allows for transparent pixels. Both GIMP and Photoshop can do this.
Perhaps you want to recreate the image as vector art, using a vector image editor? That's possible in Adobe Illustrator, and also in the free software Inkscape. It's also possible to auto trace raster images into vectors using these pieces of software, however the results are never as good as recreating the vector art manually.