GitHub Pixel Diff

Name: GitHub Pixel Diff
Author: illusionist nemo

By: illusionist nemo Add-on

Adds a pixel-level image diff to the image viewer on GitHub and GitLab — next to 2-up, Swipe and Onion Skin.

Overview

Firefox Add-ons Store

Daily users

Data as of 2026-10-13

Version:

0.18.1

Last updated: 2026-09-28

Features & Capabilities

GitHub and GitLab both show you two versions of an image. Neither shows you what changed between them.

Pixel Diff adds a fourth mode next to 2-up, Swipe and Onion Skin — in GitHub's image viewer and in GitLab's merge requests. It compares the two images pixel by pixel, paints every difference red, and crops the result to the area that actually changed — so a three-pixel shift in a long screenshot is a three-pixel shift you can see, not a picture you have to hunt through.

A threshold slider: raise it to ignore compression noise, lower it to catch everything.
Before / after / diff, and all three side by side, sharing one scale and one crop.
Images that changed size are aligned and compared anyway.
SVG and other vector images are rasterised before comparison.
Works on the images the site has already loaded — nothing is uploaded anywhere.
A GitLab of your own: add its address on the settings page, grant access, and the mode appears in that instance too.
No merge request at hand? Two images of your own compare the same way at https://nemo-illusionist.github.io/gh-pixel-diff/

The comparison runs in your browser, in a background thread. The extension has no server, collects nothing, and sends nothing.

Open source: https://github.com/Nemo-Illusionist/gh-pixel-diff

User Growth & Download Statistics

Add-on

By:

illusionist nemo

Daily users:

Version:

0.18.1 Last updated: 2026-09-28

Version code:

6521970

Creation date:

2026-09-08

Firefox add-on GUID:

gh-pixel-diff@nemo-illusionist.github.io

Firefox add-on numeric ID:

3068583

Firefox on Android:

Yes

Risk:

Permissions:

Host permissions:

https://viewscreen.githubusercontent.com/*
https://gitlab.com/*

Content scripts matches:

viewscreen.githubusercontent.com
gitlab.com

Size:

111.56KB

URLs:

Website ,Privacy policy

Full description:

Source:

Firefox Add-ons Store

Data ingested on:

2026-10-13

Compare stats and ranking:

Contact the developer

Chrome-Stats does not own this Firefox add-on. Please use these information below to contact the Firefox add-on developer.

Developed by:: illusionist nemo
Firefox Add-ons Store: https://addons.mozilla.org/firefox/addon/github-pixel-diff/
Website:: https://github.com/Nemo-Illusionist/gh-pixel-diff

Is GitHub Pixel Diff Safe?

Risk impact

Risk impact measures the level of extra permissions an extension has access to. A low risk impact extension cannot do much harms, whereas a high risk impact extension can do a lot of damage like stealing your password, bypassing your security settings, and accessing your personal data. High risk impact extensions are not necessarily malicious. However, if they do turn malicious, they can be very harmful.

GitHub Pixel Diff requires a few sensitive permissions. Exercise caution before installing.

Risk impact analysis details

High Injects scripts into web pages, which may alter or extract site contents, resulting in a substantial risk.
High ******* ****** ** *** ********* ******** ********************** **********

Risk likelihood

Risk likelihood measures the probability that a Firefox add-on may turn malicious. This is determined by the publisher and the Firefox add-on reputation on Firefox Add-ons Store, the amount of time the Firefox add-on has been around, and other signals about the Firefox add-on. Our algorithms are not perfect, and are subject to change as we discover new ways to detect malicious extensions. We recommend that you always exercise caution when installing a Firefox add-on.

GitHub Pixel Diff is recently added, and hasn't been around long enough for us to gather enough data to accurately assess its risk level.

Risk likelihood analysis details

High This extension was recently updated in the past month. New updates may not be stable or safe.
High **** ********* *** *** **** ****** ********* ********** *** *** ** ****** ** *****
Medium **** ********* *** ***** ** *** **** * ******* *** ********** *** *** ** ****** ** *****