CGX File

What are CGX files and how to open them

Are you having problems opening a CGX file or are you simply curious about its contents? We're here to explain the properties of these files and provide you with software that can open or handle your CGX files.

What is a CGX file?

CGX files have multiple uses, and CGFX Commodore Grafix Format is one of them. Read more about the other uses further down the page.

CGFX Commodore Grafix Format

Commodore Grafix files are image and animation containers designed for the C64 OS environment to store graphics in a flexible, modern way. They wrap various Commodore 64 native and non-native video modes (like high-resolution, multicolor, character-based, etc.) into a single format that allows metadata, variable frame sizes, multiple frames, and relationships between frames. Purposes include storing panoramas (multiple images forming a wide scene), matrices for viewing 3D models interactively, animated sequences with controlled frame rate and loop behavior, and also simple still images.

The format is created and used by C64 OS, starting with version 1.04 (the "Multimedia Release"), which introduced support for these files in its Image Viewer and a companion tool called CGFX Creator. The Creator tool helps assemble raw image data (from frames) together with headers, metadata, and configuration for things like wrap-around behavior, frame count, and video mode. The resulting file can then be viewed or interacted with in C64 OS's Image Viewer.

Internally, the format uses a RIFF (Resource Interchange File Format) container structure with "CGFX" as its media identifier. A valid file begins with the ASCII signature "RIFF", followed by size fields and then a chunk identified by "CGFXMETA". Within the data section are one or more frames, each composed of ordered components (such as bitmap data, character set, charmap, colormap, border color, background colors) depending on the video mode and attributes.

If a file matches this description - with the "RIFF" signature at offset zero and "CGFXMETA" around offset eight, containing the strings "CGFX" and "META" - then it is a proper Commodore Grafix format file.

How to open CGX files

Important: Different programs may use files with the CGX file extension for different purposes, so unless you are sure which format your CGX file is, you may need to try a few different programs.

While we have not verified the apps ourselves yet, our users have suggested two different CGX openers which you will find listed below.

Last updated: August 31, 2026

All known file formats using extension .CGX

While CGFX Commodore Grafix Format is a popular type of CGX-file, we know of 2 different uses of the .CGX file extension. Different software may use files with the same extension for different types of data.

CommonGraph File

We know that one CGX format is CommonGraph File. We have not yet analyzed in detail what these files contain and what they are used for. We're working on it.

Various apps that use files with this extension

These apps are known to open certain types of CGX files. Remember, different programs may use CGX files for different purposes, so you may need to try out a few of them to be able to open your specific file.

Help us help others

File.org helps thousands of users every day, and we would love to hear from you if you have additional information about CGX file formats, example files, or compatible programs. Please use the links below or email us at submit@file.org to discuss further.