TweakPNG is a low-level utility for examining and modifying PNG image files. It supports Windows XP and higher. In order to make much use of it, you will have to be at least somewhat familiar with the internal format of PNG files. For information about PNG, see the PNG home page.

A screenshot of TweakPNG:

screenshot of TweakPNG

To download TweakPNG, save the following link: (about 500K) 2014-09-07

You can also view the README file.

Development is hosted at GitHub.

To install it, extract the files in the ZIP file to a location of your choice (e.g. C:\Program Files\). To run it, open either x86\tweakpng.exe, or, if you’re using an x64 64-bit edition of Windows, x64\tweakpng.exe.

TweakPNG is free software, distributed under the terms of the GNU General Public License (GPL) version 3. The C++ source code for TweakPNG is included the zip file.


v1.4.6 (7 Sep 2014) (download):

v1.4.5 (26 Dec 2012) (download):

v1.4.4 (24 Aug 2012) (download):

v1.4.3 (6 Mar 2012) (download):

v1.4.2 (9 Aug 2011) (download):

v1.4.1 (9 Jan 2011) (download):

v1.4.0 (5 Jun 2010) (download):

v1.3.2 (22 Aug 2009) (download):

v1.3.1 (7 Dec 2008) (download):

v1.3.0 (16 Nov 2008) (download):

v1.2.1 (11 Dec 2004) (download):

v1.2.0 (29 Dec 2003):

v1.1.2 (24 Nov 2003):

v1.1.1 (3 Jan 2001):

v1.1.0 (28 Dec 2000):

v1.0.1 (27 Dec 1999):

v1.0.0 (3 Dec 1999):

TweakPNG was written by Jason Summers. You may send comments and questions about TweakPNG to