The graphics that you see in a standard vBulletin installation are not standard graphics. They started life as 3D objects and scenes created in an application called Lightwave 3D. The resulting rendered images were then post-processed using Adobe Photoshop.

3D graphics work differently from normal graphics—the edges of the images do not end in a sharply defined pixel border. Instead they are matted to a specific background color. If you use the default background colors in vBulletin, then everything will be fine. However, if you change the background colors of the page, then you may need to do some work on the graphics. To make this easy the vBulletin developers have made available two versions of the Graphics Developer Kit. (You can download them from the vBulletin Members' Area.) The first kit contains fully prepared images, and all you need to do is choose the matte color and save the images. The second kit contains much larger layered images that allow you to make numerous changes to the look of the graphics before saving them.