Computers display graphics in either vector or bitmap format. Understanding the difference between the two formats can help you work more efficiently with them. Flash lets you create and animate compact vector graphics. It also lets you import and manipulate bitmap graphics that have been created in other applications.
Vector graphics describe images using lines and curves, called vectors, that also include color and position properties. For example, the image of a leaf is described by points through which lines pass, creating the shape of the leaf's outline. The color of the leaf is determined by the color of the outline and the area enclosed by the outline.
When you edit a vector graphic, you modify the properties of the lines and curves that describe its shape. You can move, resize, reshape, and change the color of a vector graphic without changing the quality of its appearance. Vector graphics are resolution-independent, meaning they can be displayed on output devices of varying resolutions without losing any quality.
Bitmap graphics describe images using colored dots, called pixels, arranged within a grid. For example, the image of a leaf is described by the specific location and color value of each pixel in the grid, creating an image much in the same manner as a mosaic.
When you edit a bitmap graphic, you modify pixels, rather than lines and curves. Bitmap graphics are resolution-dependent because the data describing the image is fixed to a grid of a particular size. Editing a bitmap graphic can change the quality of its appearance. In particular, resizing a bitmap graphic can make the edges of the image ragged as pixels are redistributed within the grid. Displaying a bitmap graphic on an output device that has a lower-resolution than the image itself also degrades the quality of its appearance.