| Format | Typical Compression Ratios | Description |
|---|---|---|
| GIF | 4:1 - 10:1 | Lossless for images 256 colors. Works best for flat color, sharp-edged art. Horizontally oriented bands of color compress better than vertically oriented bands. |
| JFIF (JPEG) | 10:1 - 20:1 | High quality - has little or no loss in image quality with continuous tone originals. Worse results for flat color, sharp-edge art, and bilevel images. |
| 30:1 - 50:1 | Moderate quality - usually the best choice for the Web. | |
| 60:1 - 100:1 | Poor quality - suitable for thumbnails and previews. Marked blockiness and Gibb's effect occur. | |
| PNG | 10-30% smaller than GIFs | PNG's behave similarly to GIFs only better; they work best with flat-color, sharp-edged art. PNGs compress both horizontally and vertically, so solid blocks of color generally compress best. |
Last updated on 02/11/2003 by L.M. Hicks