Edge 840 ScreenShots show up as icons only

Edge 840 has ability to take screenshot by pressing the power button. To see the screen shots, the Edge has to mount as a drive. I am using an iMac, which does not recognize the MTP protocol (I think it's Android). So I am using Open MTP. It shows all the files and folders, but the files in the ScreenShot folder are all icons only, in the format .BMP. Cannot be opened at this point. When I copy the file to my desktop, it becomes a .SVG file. It is just an icon, tiny at 918 bytes (4KB on disk)