Operation Manual

Last updated 12/5/2011

Chapter 4: Understanding and opening

images

For detailed instructions, click the links below. To ask questions, request features, or report problems, visit

feedback.photoshop.com.

Image essentials

About bitmap images

Bitmap images—technically called raster images—use a rectangular grid of picture elements (pixels) to represent

images. Each pixel is assigned a specific location and color value. 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 more efficiently represent subtle gradations of shades and

color.

Bitmap images are resolution-dependent—that is, they contain a fixed number of pixels. As a result, they can lose detail

and appear jagged if they are scaled to high magnifications on-screen or if they are printed at a lower resolution than

they were created for.

Example of a bitmap image at different levels of magnification

Bitmap images sometimes require large amounts of storage space, and often need to be compressed to keep file sizes

down when used in certain

Creative Suite

components. For instance, you compress an image file in its original application before you import it into a layout.

Note: In Adobe Illustrator, you can create bitmap effects in your artwork using effects and graphic styles.