Bitmap and Vector Images in Adobe Photoshop CS5
Photoshop Creative Suite 5’s ability to use both bitmap and vector images gives you, as a designer, incredible opportunities when combining the two technologies. You may have already discovered that Photoshop works a little differently from most other applications.
To create those smooth gradations from one color to the next, Photoshop takes advantage of pixels. Bitmap images (or raster images) are based on a grid of pixels. The grid is smaller or larger depending on the resolution you’re using.
The number of pixels along the height and width of a bitmap image are the pixel dimensions of an image, measured in pixels per inch (ppi). The more pixels per inch, the more detail in the image.
Unlike vector graphics (mathematically created paths), bitmap images can’t be scaled without losing detail. Generally, you should use bitmap images at or close to the size you need. If you resize a bitmap image, it can become jagged on the edges of sharp objects. On the other hand, you can scale vector graphics and edit them without degrading sharp edges.