Compression reduces the data needed to represent information. Lossless compression allows the original data to be reconstructed exactly. Lossy compression discards some information to achieve a smaller representation. The appropriate method depends on the content and intended use. Text and source code require exact preservation. Photographs can sometimes tolerate changes that are less noticeable at normal viewing size. The amount and type of loss affect quality, and repeated lossy edits can introduce additional degradation. A smaller file is not automatically a better file. Check whether fine detail, edges, or text remain readable. Keep the original when future editing may be needed. Converting an already degraded image to a lossless format prevents further compression loss but does not restore missing detail. Practice: Explain why a source-code archive and a web photograph may use different compression approaches. Name the information each workflow must preserve.