- File type: Canon Catalog Index
- MIME: application/binary
What is a CTG File extension
The CTG file extension is in the area of digital photography and video recording.
This particular format is part of the Canon brand of digital cameras and recorders. There it serves as the representation for catalog index files created in the canon digital cameras memory card of the device. And it normally resides within the folder CANONMSC.
Folder CanonMSC
The device in the memory card automatically creates this folder. It usually corresponds to other folders stored in the memory card used by the Canon devices. As a catalog, the CTG format file normally contains data on the number of images stored (or used to be stored) within the different folders created in the memory card.
The images commonly have a limit of 99 images associated with a catalog file. And anything that exceeds this number would prompt the creation of a new CTG format file.
One cannot open or edit this file manually. And it will be automatically deleted or erased by the camera device once the associated files are no longer present in the unit.
How to open CTG Files on Windows and MAC
Instructions
- Search for the .ctg in your device.
- Double click on it
- Select open with option
- From the drop down list of apps and software select the viewer, app or program zoombrowser. If there is not any viewer installed you will have to download one of the programs we mentioned in the previous section.
- You can also try an hexadecimal editor like Ultraedit, HXD or Winhex
Programs
- Launch and Open one of the viewers installed: zoombrowser from cannon
- From the application go to the menu of files to open the .ctg file from your device.
- Now you can view the format in the app.

The image Size
FAQ
How do I convert CTG file to JPEG
The conversion is not possible. The CTG don’t have any image data inside.
Can I delete a CTG?
You can, but anytime you do it your canon camera will create it again.