GIF is one of the most common raster image formats. Its name is an abbreviation for Graphics Interchange Format File. The developer is the CompuServe organization. A feature of this particular image format is its ability to support the animation function. You can edit animated GIFs in different programs (for example, Easy GIF Animator). Animation is achieved due to the fact that a file of this format carries in itself in a certain sequence several raster images at once. With a depth of up to 256 colors, significant data compression in GIF files is possible without loss of quality.
PNM is a raster image category format. This is a bitmap bitmap created in Portable Any Map format. As you know, this format was intended from the very beginning to process some types of portable monochrome black and white images (PBM), color images (PPM) and grayscale images with shades of gray (PGM). Allows the inclusion of raster graphics data in the .PBM, .PGM or .PPM format. Such formats can provide an intermediate representation of data during the conversion of raster graphic files by different platforms. Separate applications support these three formats directly because they are defined as the PNM format. Able to be stored using binary data or ASCII text. PNM is the common format for the Netpbm package. It contains intermediate files that are used when it comes to converting several open source programs called Portable Bitmap. The PPM format was developed by J. Poskanzer. This is the easiest format for storing graphics. PNM files store one image. They do not apply compression. To view and process a bitmap image in PNM format, you can use programs such as GIMP, ImageMagick, Newera Graphics Converter Pro, XnViewMP. The same programs are able to convert images of this format.