Inside a bitmapped image is a collection of picture elements, also known as pixels .
Bitmapped images are resolution-dependent.
This means that when you create a file, you must specify a resolution. When you change the resolution, the image becomes degraded. They also can be transformed using image-editing filters to create a range of special effects and natural looks. Vector illustrations, by contrast, store each image as a series of instructions on how to draw the object. Because drawing instructions are usually much simpler and can be highly compressed, vector files are usually much smaller than their bitmapped counterparts.