Most of us love loading or downloading pictures on our computer and often see the suffixes such as .gif or .jpg/.jpeg. These are the two most common inline image formats or file types.
GIF stands for General Image Format. This format was invented by Compuserve and is the most common format on the World Wide Web. It is basically a collection of pixels that together form a picture.
With images in this particular format, you are limited to a maximum of 256 colours for each picture. Of course, these colours are not fixed and for a picture of an elephant, the colour-table would have only the shades of grey. Since, each of the original colours are represented by the closest shade to it, the picture created is very close to the original colours. Therefore, GIF format is good for pictures with large single shade areas (a maximum of 256) such as buttons and lines etc.
JPEG or JPG: (.jpeg or .jpg)
This stands for Joint Photographic Experts Group. We must remember that IBM and IBM compatibles running lower than Windows 95 only allow 3 letter suffixes (.jpg) whereas others such Amiga, Unix and Windows 95 and higher allow 4 letter suffixes (.jpeg). The advantage of this over the GIF is that it is not limited to 256 colours but can incorporate millions more. Thus, it supports images with no large mono-coloured images.
This is why, for photogaphs, JPEG or JPG is preferred over GIF.
* JPEG file size is not determined by number of shades.
* Extremely compressed JPG images can look very blotchy, if not grainy.
* A compressed file must be decompressed to display and for this process, JPEG files can take much longer than GIF files.
* There are two formats of GIF – GIF87 and GIF89
The GIF89 format allows you to make one of the colours in the image transparent = that of the background.