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.
PCX is one of the first bitmap image formats developed by ZSoft for the PC Paintbrush program. This is the original bitmap format for the DOS / Windows platform. It supports monochrome single-bit black and white images, an eight-bit gray scale, indexed color images, and full-color 24-bit RGB model images. But there is no support for additional color and alpha channels, clipping paths, color management. The format provides for the application of the simplest compression algorithm (RLE) so that information is not lost. Now it has a purely historical significance. The PCX file format has been replaced by newer image formats. However, the format is still used in separate applications in order to scan and send faxes. PCX multi-page fax documents use the .DCX extension. Most DOS-based programs are suitable for viewing PCX (PC eXchange) files. In particular, the viewer Norton Commander. The big drawback of the PCX format is that it has too many versions. This can be explained by the fact that the PCX standard is open, and therefore it has been widely used by most independent software developers. And therefore it is constantly updated.