JPEG is the most common and popular bitmap format. The form got its name from the name of the organization-developer Joint Photographic Experts Group. Files of this format are used today in all digital cameras and cameras. They have a good compression ratio and support 24-bit color depth. Since such compression significantly reduces image size with virtually no loss of quality, JPEG format is widespread on the Internet. However, the stronger the compression, the worse the quality. In addition, the JPEG format does not support the transparency option.
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.