This format contains uncompressed RAW images, and it is used to create photos for archival storage. It has a TIFF structure and is distributed with open source. DNG is also used for the intermediate storage of digital images. It is supported by most camera manufacturers. It was developed by Adobe. It can be used to store multiple images, one of which is used for previews.
PGM is a storage format for grayscale images. Files in this format can be opened using software: ACDSee Photo Manager 14, ACD Systems Canvas 15, Corel PaintShop Pro X4. This type of file can be edited with a text editor. PGM files can be in two versions: P2 / P5. P2 are readable, P5 - to binary formats.