JPF is a raster image category file format that is the successor to the .JPEG image format. Like some other file name extensions (.jpx, .jp2, .j2k), the .jpf extension refers to the JPEG 2000 image format. It is needed to designate the JPEG 2000 Image file type. And JPEG 2000 files are an international standard (ISO / IEC 15444) bitmap format. It was developed by the Joint Photographic Experts Group, JPEG. It serves as a good replacement for the JPEG standard, which is older, but, as before, is in demand and widespread. Compared to JPEG in JPF format, wavelet compression is used, due to the alpha channel transparency is supported, as well as a variety of color models. Also, compared to JPEG, this format provides better scalability of images, provides the ability to achieve smaller file sizes and have a higher level of quality. The format is able to combine compression with losses and without losses. Provides support for image transparency and additional metadata information. It can be viewed in QuickTime Player 7, as in recent versions of Photoshop, provided that the JPEG2000.8bi plugin is installed. Many images also have the extension .JP2 or .JPX.
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 The PCX file format has been replaced by newer image formats.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.