TweakPNG is a low-level utility for examining and modifying PNG image files. The current version requires Windows 2000 or higher (XP, Vista, etc.), though it is possible to build a copy that runs on Windows 95/98/ME. In order to use it, you will need 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 450K) 26 Dec 2012

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.


v1.4.5 (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