MNG is an image file category format. It supports all possible PNG and JPEG compression algorithms (including gamma correction and translucency) in order to create animated images. It was available in the Mozilla browser from 2000 to 2003. Now supported by Konqueror browser. MNG, i.e. Multiple-image Network Graphics, has the closest connection with PNG. In 1995, when they started developing the PNG format, it was decided not to include animation support. For a simple reason: then this feature was used infrequently. And yet, we started working on MNG, that is, the version of PNG that supports animation. The initial version of the MNG specification was born in early 2001. The MNG format is a simplified raster analogue of Adobe Flash. Each frame has many layers, and they can be moved relative to each other, scaled, cropped. This explains the complexity of supporting the MNG format. As a result, the MNG file structure resembles the PNG structure. The only difference is the identification tag. And also that much more options of blocks (chunk) are applied. MNG frames are saved as PNG or JNG. Compared to GIF, this format supports animation. Compared to JPEG, it provides the smallest file size due to compression loss. Compared to PNG, compression is done without distortion. Now MNG is not supported by popular browsers and software, since it was replaced by a simpler APNG format.
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 The PCX file format has been replaced by newer image formats.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.