Either they are a directly replaceable font that you can use in just about any word processor, like Microsoft Word, or they are a series of bitmap images that must be used with a specialized program.
Once the bitmaps are created, you can generate larger graphics, demo images, or even web counters by putting the individual bitmap characters together.
Save the file as a Windows Bitmap (.bmp) file directly in your Windows directory (usually C:/Windows).
Adobe Photoshop is a sophisticated image manipulation utility specializing in faster bitmap images.
Some sprites can be made from CGI, while other sprites are simple eight by eight bitmap images.
Save your picture as a Bitmap (BMP) and you're done!