Graphics Interchange Format, GIF (CompuServe GIF) is a graphics format widely used on the World Wide Web, both for images and for animations. The format was developed by CompuServe in 1987 to provide a color image format for their file downloading areas, replacing their earlier RLE format in black and white. GIF became popular because they could use the LZW compression algorithm (Lempel Ziv Welch) for compressing the image, which was more efficient than the algorithm Run-length encoding (RLE) used by the PCX and MacPaint formats. Therefore, large images could be downloaded in a reasonable period of time, even with very slow modems.
Simple graphic format in color. Use 24 bits per pixel: 8 for red, 8 for green, 8 for blue if the maximum gray value is 255, uses 16 bits for red, 16 for green and 16 for blue if the value is greater than 255 and less than 65536. a PPM file is plain text and can be modified with a single processor, there is also not readable binary version of word processing normally. It is related to the PGM (grayscale) and PBM formats (black and white).