Pngcrush

pngcrush is a free, open source command-line utility for optimizing PNG image files. It reduces the size of the file losslessly — that is, the resulting "crushed" image will have the same quality as the source image.

The main purpose of pngcrush is to reduce the size of the PNG IDAT datastream by trying various combinations of compression methods and delta filters. However, pngcrush can also be used for various manipulations of PNG images, such as changing the bit depth, removing unwanted ancillary chunks, or adding certain chunks including gAMA, tRNS, iCCP, and textual chunks.

Read more about Pngcrush:  Main Operation, Reducing Filesize By Removing Color-correction Data, Image Manipulation, Chunk and Metadata Manipulation

Other articles related to "pngcrush":

Pngcrush - Chunk and Metadata Manipulation
... With pngcrush, a user can edit or remove those ancillary chunks pngcrush -res 96 -rem time -text b "Software" "pngcrush" image1.png image2.png The above command sets the image resolution to 96 dpi ...
Portable Network Graphics - File Size and Optimization Software - Optimizing Tools - Ancillary Chunk Removal
... For removing ancillary chunks, pngcrush and PNGOUT have the ability to remove all color correction data from PNG files (gamma, white balance, ICC color profile, standard ... The following command line options achieve this with pngcrush pngcrush -rem gAMA -rem cHRM -rem iCCP -rem sRGB InputFile.png OutputFile.png ...