May 26, 2018
Checks the integrity of PNG images
pngcheck verifies the integrity of PNG, JNG and MNG files by checking the internal 32-bit CRCs [checksums] and decompressing the image data; it can optionally dump almost all of the chunk-level information in the image in human-readable form. For example, it can be used to print the basic statistics about an image dimensions, bit depth, etc.; to list the color and transparency info in its palette assuming it has one; or to extract the embedded text annotations. This is a command-line program with batch capabilities.
pngsplit - break a PNG, MNG or JNG image into constituent chunks numbered for easy reassembly
png-fix-IDAT-windowsize - fix minor zlib-header breakage caused by older libpng