Large sized pictures take a large amount of space to store them. For example, Kodak Photo CD's are often 3072 pixels x 2048 pixels. Stored uncompressed, this would take 18,874,368 bytes! (since a byte is a group of 8 bits).

Thus, color pictures require massive storage - on the order of millions of bits for an 8 x 11 picture.

Storage that doesn't lose any value of the pixels - i.e., it can be recreated as it was originally - is called lossless; storage that does lose values is called lossy.

A simple method of compression is run-length encoding.

The Joint Photographic Experts Group ( JPEG ) compression algorithm compresses by removing redundant information.