Computer Graphics Metafile (CGM) is free, platform-independent, international standard metafile format for storing and exchanging vector graphics (2D), raster graphics, and text. CGM uses an object-oriented approach and many function provisions for image production. CGM uses these object-oriented characteristics for remolding graphical elements to render an image. A metafile contains necessary information that defines other files. In CGM, a text-based source file contains all graphical elements that can be later compiled into a binary file.
Files with PPSM extension represent Macro-enabled Slide Show file format created with Microsoft PowerPoint 2007 or higher. Another similar file format is PPTM which differs in opening with Microsoft PowerPoint in editable format instead of running as Slide Show. When run as slide show, the PPSM file shows the presentation slides with contents intact in the slide show and is in read-only mode by default. PPSM files can still be edited in Microsoft PowerPoint by opening it in PowerPoint.
You can also convert CGM into many other file formats. Please see the complete list below.