---
name: "png-fix-IDAT-windowsize"
section: "1"
platform: "linux"
package: "pngcheck"
version: "3.0.3-3"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/png-fix-IDAT-windowsize"
---

# png-fix-IDAT-windowsize(1)

utility to reset first IDAT's zlib window-size bytes and fix up CRC to match.

## NAME

png-fix-IDAT-windowsize - utility to reset first IDAT's zlib window-size bytes and fix up CRC to match.

## SYNOPSIS

**png-fix-IDAT-windowsize** \[*options*\] *pngfile* \[*pngfile* ...\]

## DESCRIPTION

png-fix-IDAT-windowsize, version 1.0 of 31 October 2020, by Greg Roelofs.

Uses explicit, hardcoded compression settings and line filters, writing result to output file with extension "-fixed.png".

This software is licensed under the GNU General Public License. There is NO warranty.

## OPTIONS

- **-force**

  overwrite existing output files

- **-verbose**

  print more status messages (synonym: **-noquiet**)

## SEE ALSO

[**pngcheck**(1)](/pngcheck/1.md), [**pngsplit**(1)](/pngsplit/1.md)