TweakPNG

TweakPNG is a lightweight and portable piece of software that allows you to edit the properties of image files with the PNG format, as the name implies. But it also supports the MNG and JNG file types.

Since installation is not a prerequisite, you can save the program files to any location on the hard disk and run the executable file immediately.

It is also possible to move TweakPNG to a USB flash drive or other similar storage unit, in order to run it on any workstation with minimum effort.

The most important aspect is that the Windows Registry area does not get entry updates, and files do not remain on the hard drive after removing the program.

The interface of the application is represented by a standard window with an uncomplicated layout, where you can load pictures using either the file browser or "drag and drop" function.

The main frame shows the length, CRC value, attributes and contents for each chunk type. It is possible to edit the PNG header, physical pixel size, ICC profile name, file gamma and chromaticities, among other file properties.

You can verify the validity of a file and set the file type signature, combine all IDAT chunks or split them, import and export chunks, as well as insert various image attributes (e.g. background color, end of image, palette, aspect ratio, time of last modification).

Other options of TweakPNG let you specify the compression level for new zTXt chunks, integrate the program into the context menu, access an image viewer, as well as configure the tools to list in the Tools menu.

The application is very light on the system resources, using a minimum quantity of CPU and system memory. It has a good response time and works well, without making the operating system hang, crash or pop up error dialogs. In conclusion, TweakPNG delivers a simple solution to editing some PNG, MNG and JNG file properties, and it can be easily used.