A cng file extension is related to the National Geographic image file format developed by Priority Software.
There is one other file type using
the CNG file extension!
.cng - CryptoNG encrypted data
CNG file extension - National Geographic image
What is cng file? How to open cng files?
File type specification:
The cng file extension is associated with some image files encoded by Priority Software applications.
It seems the company is no longer in business and the current usage of this format is unclear.
This cng file type entry was marked as obsolete and no longer supported file format.
This type of file is no longer actively used and is most likely obsolete. This is typically the case for system files in old operating systems, file types from long discontinued software, or previous versions of certain file types (like documents, projects etc.) that were replaced in higher versions of their original programs.