This format was used for storing databases on the Pegasus and Palm PDA devices. Besides images, PDB allowed you to store tables, maps, e-books, and other data in a structured way. Today it has become obsolete and has been replaced by more flexible formats with DRM protection.
JPG extension was assigned to the image files. Many photos and web graphics are saved in JPG. In order to compress many bitmaps are saved in .jpg, that makes it easier to transfer and download these files on the Internet. JPG format based on the 24-bit color palette, the higher the level of compression applied to create the file JPG, the greater the decompression effect on image quality.