PXM is the movie capture format of PCSX, a PlayStation emulator.
File extension pxm is used by graphic editor for Mac platform called Pixelmator. Pxm file extension is a graphic file type (similar to Adobe Photoshop PSD graphic file). Pxm file can contain complex graphic elements, layers, effects, bitmaps etc. It is not simple bitmap image like jpg or png. For opening and editing pxm file you will need Pixelmator for Mac and an Apple computer. Application is not under Windows platform.