One of the most important considerations, often ignored in websites is the format of the images that are included in a site. There are 3 basic image formats that are considered a part of the HTML (hypertext mark up) language, each of which has it's advantages and disadvantages.

1. GIF

   The Compuserve .gif (graphics image format) format has been around for ages, and is the default standard for images. One disadvantage is that there are only a maximum of 256 colors allowed in the image, which is little trouble for black and white or basic graphic images, but bad for color photos. The real disadvantage, is that the files are uncompressed otherwise, and can end up being huge, especially if the images dimensions are large. Plain GIFs should be avoided if possible in favor of the JPG format.

   GIF's can also be animated, which make them the preferred way of showing moving images on web pages. An animated .gif actually contains all of it's individual images, which are displayed in timed sequence, set during the file creation process. This also makes animated GIFs very large for the size of the resulting image, but it's a small price to pay for this great feature.

   Another wonderful aspect of GIF's is that they can be made with 'transparent' areas, usually the image background. This allows them to be placed over different colored backgrounds or other images, without their edges or other parts showing, or masking the background.

2. JPG

   The Joint Photo Group .jpg (or jpeg) format is the principle method of encoding photos, and offers 16 million colors and impressive file compression techniques that can make very compact files out of very large images. Compression can be set when saving the scanned image to the JPG file which can reduce the images detail if to aggressively applied. Compressions in the range of 20-50% are commonly used with little visible deterioration of the displayed image, but it is an inherently 'lossy' format that reduces the images quality with each new save. Simple graphic images can be compressed even further, and this is where the JPG format really shines for web developers. JPG is a nearly ideal format for the web and it has been improved with a newer "progressive" encoding method that allows images to be presented fully, in a lower detail form while they are still loading, instead of the traditional line by line sequential format that is common today.