Collection of graphics images created to test PNG applications like viewers, converters and editors. As far as that is possible, all formats supported by the PNG standard are represented.

libungif is the old GIF decompression library by the GIFLIB project.

Slurp can select a region in a Wayland compositor and print it to the standard output. It works well together with grim.

Exiv2 is a C++ library and a command line utility to manage image metadata. It provides fast and easy read and write access to the Exif, IPTC and XMP metadata of images in various formats.

Imlib2 is a library that does image file loading and saving as well as rendering, manipulation, arbitrary polygon support, etc.

It does ALL of these operations FAST. Imlib2 also tries to be highly intelligent about doing them, so writing naive programs can be done easily, without sacrificing speed.

This is a complete rewrite over the Imlib 1.x series. The architecture is more modular, simple, and flexible.

Libiptcdata is a C library for manipulating the International Press Telecommunications Council (IPTC) metadata stored within multimedia files such as images. This metadata can include captions and keywords, often used by popular photo management applications. The library provides routines for parsing, viewing, modifying, and saving this metadata.

Libmng is the MNG (Multiple-image Network Graphics) reference library.

GIFLIB is a library for reading and writing GIF images. It is API and ABI compatible with libungif which was in wide use while the LZW compression algorithm was patented. Tools are also included to convert, manipulate, compose, and analyze GIF images.

pngcheck verifies the integrity of PNG, JNG and MNG files (by checking the internal 32-bit CRCs, a.k.a. 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 (e.g. pngcheck *.png.)

Also includes pngsplit which can split a PNG, MNG or JNG file into individual, numbered chunks, and png-fix-IDAT-windowsize that allows resetting first IDAT's zlib window-size bytes and fix up CRC to match.

VIGRA stands for Vision with Generic Algorithms. It is an image processing and analysis library that puts its main emphasis on customizable algorithms and data structures. It is particularly strong for multi-dimensional image processing.

OptiPNG is a PNG optimizer that recompresses image files to a smaller size, without losing any information. This program also converts external formats (BMP, GIF, PNM and TIFF) to optimized PNG, and performs PNG integrity checks and corrections.

jpegoptim provides lossless optimization (based on optimizing the Huffman tables) and "lossy" optimization based on setting maximum quality factor.

Gpick is an advanced color picker and palette editing tool.

The JasPer Project is an initiative to provide a reference implementation of the codec specified in the JPEG-2000 Part-1 standard (i.e., ISO/IEC 15444-1).

SNG (Scriptable Network Graphics) is a minilanguage designed specifically to represent the entire contents of a PNG (Portable Network Graphics) file in an editable form. Thus, SNGs representing elaborate graphics images and ancillary chunk data can be readily generated or modified using only text tools.

SNG is implemented by a compiler/decompiler called sng that losslessly translates between SNG and PNG.

Libavif is a C implementation of AVIF. It can encode and decode all YUV formats and bit depths supported by AOM, including with alpha.

Imlib2 is a library that does image file loading and saving as well as rendering, manipulation, arbitrary polygon support, etc.

It does ALL of these operations FAST. Imlib2 also tries to be highly intelligent about doing them, so writing naive programs can be done easily, without sacrificing speed.

This is a complete rewrite over the Imlib 1.x series. The architecture is more modular, simple, and flexible.

APNG (Animated Portable Network Graphics) is an unofficial extension of the APNG (Portable Network Graphics) format. APNG patch provides APNG support to libpng.

libjpeg-turbo is a JPEG image codec that accelerates baseline JPEG compression and decompression using SIMD instructions: MMX on x86, SSE2 on x86-64, NEON on ARM, and AltiVec on PowerPC processors. Even on other systems, its highly-optimized Huffman coding routines allow it to outperform libjpeg by a significant amount. libjpeg-turbo implements both the traditional libjpeg API and the less powerful but more straightforward TurboJPEG API, and provides a full-featured Java interface. It supports color space extensions that allow it to compress from and decompress to 32-bit and big-endian pixel buffers (RGBX, XBGR, etc.).

swappy is a command-line utility to take and edit screenshots of Wayland desktops. Works great with grim, slurp and sway. But can easily work with other screen copy tools that can output a final PNG image to stdout.

Icoutils are a set of program for extracting and converting bitmaps from Microsoft Windows icon and cursor files. These files usually have the extension .ico or .cur, but they can also be embedded in executables and libraries (.dll-files). (Such embedded files are referred to as resources.)

Conversion of these files to and from PNG images is done icotool. extresso automates these tasks with the help of special resource scripts. Resources such can be extracted from MS Windows executable and library files with wrestool.

This package can be used to create favicon.ico files for web sites.

A pretty small png library. Currently all documentation resides in pnglite.h.

LodePNG is a PNG image decoder and encoder, all in one, no dependency or linkage required. It's made for C (ISO C90), and has a C++ wrapper with a more convenient interface on top.

IQA is a C library for objectively measuring image/video quality. It implements many popular algorithms, such as MS-SSIM, MS-SSIM*, SIMM, MSE, and PSNR. It is designed to be fast, accurate, and reliable. All code is Valgrind-clean and unit tested.