Both image formats can produce excellent stamps; however simple images are always best in .eps and .wmf format to allow you to easily manipulate line thickness in the event the lines are too thin.
All images that enter your computer have an extension relating to what format they are in. You may have an image from a scan, a clipart disk or downloaded from a clipart service. Some are .eps and .wmf files (Vector line format more common for logos or line drawings) and others jpeg an .gif (Bitmap pixel photos and illustrations)
When the craft of scrapbooking began, you needed to buy tons and tons of stickers, tape, glue and pretty papers just to stick on the first photo of your kids. Well now days, more and more frugal and happy scrappers are taking full advantage of the technology available to them. With digital cameras and the internet, scrapbooking has become a hobby that anyone can do, and without a huge amount of expense. There is a world of free images, clip art, fonts, borders etc. that can be downloaded or saved to your computer and printed out for your scrapbooks.