CTG is a catalog index file created on Canon digital cameras, stored in the CANONMSC folder which corresponds to other folders saved on the memory card. CTG files contain information about the number of images stored in each folder on the memory card. They should not be manually opened or edited by the user.

What program will open a CTG file?

If your CTG file is not Canon Catalog File you can use one of the hex editors like HxD, WinHex, UltraEdit to open it and view what is inside. Based on the contents of the CTG file you can try to figure the right program to open it.

How do I convert a CTG file to JPEG?

NOTE: CTG files are much smaller than . JPG files and do not contain any image data. Therefore they cannot be converted to JPEG files.