GIF file
From TrillWiki
GIF files support 1-bit transparency and 256 colors in an image, so in that aspect they are inferior to PNG files. However, they support animation. Also, since they are a lossless compressed format, they have advantages over JPG files and BMP files.
- 256 colors
- Unlike the other formats, GIF only supports 256 colors in an image. Fortunately, this is paletted, so the colors can be anything you want, but things like gradients and anti-aliasing will suffer. This also means that colors may be shifted by your graphics software, so be sure to check the final palette before setting transparent colors in your <background> code.
- Compression
- GIF uses LZW compression. The file size is usually smaller than BMP, and lossless JPEG2000.
- Lossless
- Unlike a JPG file, none of the data is lost when you compress an image using the GIF format. (Other than the initial loss of colors, of course.)
- Transparency
- Unlike a PNG file, which has 8-bit transparency, GIF has 1-bit transparency, which means things can have only 1 level of transparency, on or off.
- Patented
- Unisys owns the patent to the compression algorithm used in GIF files and was enforcing it. This prompted many to look for unpatented formats such as PNG files.
- Animation
- GIF's primary advantage (especially for Trillian skinning) is that it supports animation. However, remember that the 256 color limitation applies to the entire file, not just a single frame.
