Computer Graphic Metafile
CGM is a vector graphics format that supports three different encoding methods: binary (best for program read speed), character-based (produces the smallest file size and allows for faster data transfers) or cleartext encoding (allows users to read and modify the file with a text editor)
MIME type: image/cgm
Learn more about CGM files:
Visit the ANSI webpage
Ask about CGM files at IT Knowledge Exchange.