PCX, or officially PC Paintbrush format, was designed for MS-DOS, and was then used by Microsoft – Microsoft Paintbrush program was delivered with each copy of MS Windows. This image format was at the basis of the whole industry of computer development. Originally the format was not able to handle images consisting of more than 16 colors, but it was revised, and finally the number of colors was increased to 256. The latest variation of the PCX format supports 24-bit color images, though the compression algorithm does not allow support for images of large pixel density. The compression algorithm used is RLE, and the result of the compression is hard to foresee without knowing the exact number of colors. As a rule, the image file will lose 40%-70% of the original image if we deal with images of no more than 16 colors. If the number of colors is larger, the percentage of compression will only be in the range of 10%-30%. The PCX format is no longer widely used except for some scanning applications. Multipage PCX fax documents use the .DCX extension also supported by ImageConverter Plus. The most popular conversion with the PCX format we encounter is conversion from PCX to JPEG, though there may be a necessity to convert JPEG to PCX for different reasons. JPEG offers decent compression that is a tradeoff between the image size and the image quality. It typically achieves 10:1 compression with little perceptible loss in image quality.