Many computer users compress their files so that they have more room on disks. Lossy compression actually loses data as part of the compression process. While this type of compression would have disastrous effects on computer programs, text, and data files, lossy compression is commonly used with pictures. Because much of the data that goes into a picture may not make a difference in regards to how we see a picture on the screen, lossy compression works fairly well when compressing photos and graphics. JPEG is a well-known type of lossy compression.
Lossless compression makes files smaller without losing data.
This form of compression often is effective because most files contain repetitive data. ZIP is a common form of lossless compression. Working with compressed files Compressed files can only be copied, deleted, renamed, or decompressed. If you download a compressed version of a program off of the Web, you will need to decompress the program before you can run it. Fortunately, you can find programs that can compress and decompress files easily on the Web.