.TNL File Extension

A .TNL file is a Super Mario Maker Course Thumbnail, created by Nintendo.

Open with All Platforms. Available for .

What is a .TNL file?

A .TNL file is a type of image file specifically used in the video game Super Mario Maker, which is designed for the Wii U gaming console. This file format serves as a thumbnail image for individual game courses. When players create or modify a course in Super Mario Maker, a .TNL file is automatically generated to represent a small preview or snapshot of what the course looks like. This thumbnail helps players quickly identify and select courses within the game interface.

The .TNL files are stored within the same directory as the course files on the Wii U system. Each course directory typically includes the .TNL file along with other related files such as .CDT (course data) and .BWV (audio files), which together comprise all the necessary components of a Super Mario Maker course.

To view or manipulate .TNL files outside of the Super Mario Maker game, a specific approach is required due to the proprietary format used. Initially, these files contain an 8-byte header that must be removed before they can be accessed as standard JPEG images. After removing this header, the files can be opened and viewed using any standard image viewing or editing software that supports JPEG files.

For those looking to convert .TNL files into a more accessible format, a Python script named `` can be used. This script is designed to handle the removal of the proprietary header and convert the .TNL file into a standard JPEG file, making it easier to view and edit with common image software on various platforms.


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