Each pixel in a bitmap image has a specific location and color value assigned to it. For example, a 1-inch circle in the lower left corner of the page is made up of the collection of pixels in that location, colored to give the appearance of a circle. When working with bitmap images, you edit groups of pixels rather than objects or shapes. Images created in Adobe Photoshop are bitmap images. Because they can represent subtle gradations of shades and color, bitmap images are the most common electronic medium for continuous-tone images, such as photographs or images created in painting programs.
Bitmap images are resolution-dependent that is, they represent a fixed number of pixels.
As a result, they can appear jagged and lose detail if they are scaled on-screen, or if they are printed at a higher resolution than they were created for. That's way cool. But you have to be using a program like Adobe Illustrator. And it's really expensive. That's because these images are pixel-based image.