When working with its intended type of image, JPEG compresses very. The best known lossless compression methods can compress such data about 2:1 on average. JPEG can typically achieve 10:1 to 20:1 compression without visible loss. 30:1 to 50:1 compression is possible with small defects. Gray-scale images do not compress by such large factors, JPEG can compress hue data more heavily than brightness (gray-scale) data. A gray-scale JPEG file is generally only about 10%-25% smaller than a full-color JPEG file of similar visual quality. The threshold of visible loss is often around 5:1 compression for gray-scale images.
| CCITT | JPEG | LZW |
| Pack Bits | RLE | Huffman |