This format was created by Nokia for use in its proprietary phones. A bitmap image was used to transfer image files between devices over a wireless connection. It was mainly used when exchanging multimedia text messages that support inserting pictures.
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.