pngcheck

A Rust reimplementation of the classic pngcheck utility for verifying PNG file integrity and displaying chunk information.

Features

• PNG signature validation
• CRC-32 validation for all chunks
• Chunk structure verification
• IHDR, PLTE, IDAT, IEND critical chunks
• Common ancillary chunks (tRNS, cHRM, gAMA, iCCP, sBIT, sRGB, tEXt, zTXt, iTXt, bKGD, hIST, pHYs, sPLT, tIME, eXIf)
• Animated PNG chunks (acTL, fcTL, fdAT)
• PNG Third Edition chunks (cICP, mDCV, cLLI)
• Verbose output modes
• Color output for terminals

Usage

# Check a single PNG file
pngcheck image.png

# Check multiple files
pngcheck file1.png file2.png file3.png

# Verbose output
pngcheck -v image.png

# Very verbose output
pngcheck -vv image.png

# Colorized output
pngcheck -c image.png

# Print text chunks
pngcheck -t image.png

# Print palette contents
pngcheck -p image.png

# Quiet mode (errors only)
pngcheck -q image.png

# Read from stdin
cat image.png | pngcheck

Command-line Options

• -7 - print contents of tEXt chunks, escape chars >=128 (for 7-bit terminals)
• -c - colorize output (for ANSI terminals)
• -p - print contents of PLTE, tRNS, hIST, sPLT (can be used with -q)
• -q - test quietly (output only errors)
• -t - print contents of tEXt chunks (can be used with -q)
• -v - test verbosely (print most chunk data)
• -h - show help

Differences from original version

• Simplified output format for chunk information
• Does not include MNG/JNG support (PNG-only)
• Does not include -s (search) or -x (extract) features
• Does not decompress/validate zlib streams in IDAT chunks

Original Credits

Based on pngcheck 4.0.0 by:

• Alexander Lehmann
• Andreas Dilger
• Greg Roelofs
• Chris Lilley
• Glenn Randers-Pehrson
• John Bowler
• Tom Lane