Files with CMX extension are Corel Exchange image file format (also known as Corel Metafile Exchange) that is used as presentation by CorelSuite applications. It contains image data as vector graphics as well as metadata that describes the image. CMX files can be opened by CorelDraw, Corel Presentations, Paint Shop Pro and some versions of Adobe Illustrator. CMX files can be converted to other formats such as JPG and EPS.
Files with POTM extension are Microsoft PowerPoint template files with support for Macros. POTM files are created with PowerPoint 2007 or above and contains default settings that can be used to create further presentation files. These settings can include styles, backgrounds, colour palette, fonts and defaults along with macros that consist of custom functions for doing particular task. They may also be opened by a previous version of PowerPoint with Open XML document support installed. POTM files can be opened in Microsoft PowerPoint for editing like any other PowerPoint file.