Definition: Clip art and images that do not have a shadow may or may not have a transparent background. Unshadowed images appear to lie directly on the Web page and do not give the illusion that they stand out from the background of the Web page.
If the background of a piece of clip art or images is not transparent you will see a square or rectangle area around the image when it is placed on a Web page of a different color than the background the clip art or image was created with. An unshadowed image that is not transparent is best used on white Web pages or on very, very light Web pages.