About Bitmap Images and Vector Graphics

Photoshop Elements' painting and drawing tools render artwork in two fundamentally different ways.

The painting tools, including all the varied fills, gradients, brushes, and erasers, work by making changes to pixelsadding them, removing them, or changing their color. A bitmap image is composed entirely of tiny pixels; and digital photos, the mainstay of Photoshop Elements, are bitmap images. Although you can apply paintbrushes, color fills, special effects, and filters to bitmaps, they simply don't resize well. If you try to enlarge a digital photo, for example, you'll see that its image quality suffers as the pixels get bigger, resulting in a blurry mess.

The drawing tools (shape creation tools, really) form images not by manipulating pixels but by constructing geometric paths based on precise mathematical coordinates, or vectors. Images created with these drawing tools, known as vector graphics, hold one decided advantage over their bitmap cousins: they can be scaled up or down, virtually infinitely, with no loss of detail or resolution (Figure 8.1). Photoshop Elements' scalable fonts, for example, are based on vector shapes, so they can be stretched, warped, and resized to your heart's content. Vector graphics also tend to be smaller than comparable bitmap images, since a path shape requires less information for your computer to process and render than a similar shape constructed of pixels.

Figure 8.1. A photographic bitmap image (top) is constructed of pixels. Any attempt to zoom in on or enlarge a portion of the image can make the pixels more pronounced and the image more pixelated. A vector image (bottom) is drawn with a series of geometric paths rather than pixels. Vector graphics can be enlarged or reduced with no loss of detail or resolution.

Although they're designed to work with different kinds of graphics, Photoshop Elements' painting and drawing tools are equally easy to use, and work well together if you want to combine vector and bitmap graphicssuch as adding type or custom shapes to a favorite photo.