The partimg.gz file extension is used as Partimage. This supports most common Linux file systems, and can be found in many Linux distributions, including Debian and the Live Distros PING, Knoppix and SystemRescueCD.
How to open:
Currently there is no specific information available, about how to open this file extension.For general information try to look at:Basic info how to open backup files
How to convert:
As far as we know, this .partimg.gz file type can't be converted to any other file format. This is usually the case of system, configuration, temporary, or data files containing data exclusive to only one software and used for its own purposes. Also some proprietary or closed file formats cannot be converted to more common file types in order to protect the intellectual property of the developer, which is for example the case of some DRM-protected multimedia files.