This is a format for presenting fonts in PDF files that was initially conceived to store symbols in the Japanese and Chinese languages because it had a 16-bit structure and allowed for more precise adjustment. CID expands the the potential for PostScript by supporting languages that do not have a left-to-right orientation, and by supporting even a vertical mode of orientation.
This format is used for storing bitmap images. It supports many different file types and compression algorithms. One Palm bitmap file can contain multiple versions of the same images with different colors. These files are used on PALM devices.