niicat
August 14, 2026 · View on GitHub
This is a tool to quickly preview nifti images on the terminal. This can be helpful if you are working on a remote server via SSH and do not have a -X connection. Niicat can also display png, jpg or similar images.
Your terminal must support inline images. Ubuntu's default terminal (GNOME Terminal / Ptyxis), Apple Terminal, and Alacritty do not. When using SSH, it is the terminal on your local machine that must support the protocol.
| Flag | Protocol | Works in |
|---|---|---|
| (default) | iTerm2 imgcat | iTerm2, WezTerm, VS Code (enable terminal.integrated.enableImages) |
-kt | Kitty graphics | Kitty, Ghostty, WezTerm |
-lb / -ls | Sixel | mlterm, foot, WezTerm, Konsole, Windows Terminal, xterm (-ti 340) |
Install:
pip install niicat
Usage:
niicat T1.nii.gz
If nothing is displayed, your terminal likely does not support the selected protocol. Try another flag from the table above, or switch to a terminal that does.
-lb uses img2sixel from libsixel-bin (sudo apt install libsixel-bin).
-ls uses libsixel-python.
Niicat was only tested on python >= 3.7.
Copyright
Copyright © German Cancer Research Center (DKFZ), Division of Medical Image Computing (MIC). Please make sure that your usage of this code is in compliance with the code license.