Adobe photoshop cs2 사용자 설명서

Computer graphics fall into two main categories—bitmap and vector. You can work with both types of graphics in 
Photoshop and ImageReady; moreover, a Photoshop file can contain both bitmap and vector data. It’s helpful to 
understand the difference between the two categories as you create, edit, and import artwork. 

Bitmap images—technically called raster images—are made up of a grid of dots known as pixels. When working with 
bitmap images, you edit pixels rather than objects or shapes. Bitmap images are the most common electronic 
medium for continuous-tone images, such as photographs or digital paintings, because they can represent subtle 
gradations of shades and color. 

Bitmap images can lose detail when scaled on-screen because they are resolution-dependent, they contain a fixed 
number of pixels, and each pixel is assigned a specific location and color value. Bitmapped images can look jagged if 
they’re printed at too low a resolution because the size of each pixel is increased. 

Vector graphics are made up of mathematically defined lines and curves called vectors. You can move, resize, or 
change the color of a line without losing the quality of the graphic. 

Vector graphics are resolution-independent—that is, they can be scaled to any size and printed at any resolution 
without losing detail or clarity. As a result, vector graphics are the best choice for representing bold graphics that must 
retain crisp lines when scaled to various sizes (logos, for example).