PBM is a Portable image in black and white. Can be opened with programs: Adobe Photoshop CS, ACD Systems Canvas 15, ACD Systems ACDSee 17, Newera Graphics Converter Pro, Corel PaintShop Pro X6. File contains 1 bit per pixel. PBM is a kind of file format PPM. And can be readable or binary.
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.