This document reviews various techniques for image compression. It begins by discussing the need for image compression in applications like remote sensing, broadcasting, and long-distance communication. It then categorizes compression techniques as either lossless or lossy. Popular lossless techniques discussed include run length encoding, LZW coding, and Huffman coding. Lossy techniques reviewed are transform coding, block truncation coding, vector quantization, and subband coding. The document evaluates these techniques and compares their advantages and disadvantages. It also discusses performance metrics for image compression like PSNR, compression ratio, and mean square error. Finally, it reviews several research papers on topics like vector quantization-based compression and compression using wavelets and Huffman encoding.