This tutorial will teach you about the various image formats available.
GIF vs JPEG, which is better? JPEG is better for photos/scans and images with lots of colours. GIF is better for computer generated images, and images
with just a few colours or repeating patterns.
GIF Format - .gif
GIF stands for Graphical Interface Format, and normally uses what is known as LZW compression. This is an awesome compression algorithm, but is not available in FT Gimp due to a patent held by Unisys. FlamingText Gimp uses a different alogirithm called RLE (Run Length Encoding). This algorithm is not as good as LZW, but is not covered by the patent.
A great alternative to GIF's are PNG's.
GIF is the standard for animated images on the web, although some other
alternatives are starting to appear.
JPEG Format - .jpg/.jpeg
JPEG stands for Joint ... Group. This format is best when used for photos and
XCF Format - .xcf
This is the native format. When you are working on an image, you should save
in this format to keep all the layer information etc.
PNG Format - .png
A patent free format that is gaining wide spread popularity. It is already
accepted by all major browsers: Netscape, IE, Opera and Mozilla.