A PowerPoint Template is a file that can contain commonly used settings to make producing future PowerPoint Presentations and Shows easier. POTX PowerPoint Templates are different than the POT version in that they use the Microsoft Office Open XML format.
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.