The file stores slides with presentations and slide shows filled with graphics, audio, video, and textual information. The format is identical to the PPT file, except for the editing feature, and is a bit smaller. Can be opened only in preview mode and prevents other users from changing the structure and content of the presentation.
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.