Pngcrush optimizes PNG images. It can further losslessly compress them by as much as 40%.

sjpeg is a simple encoding library for encoding baseline JPEG files. It is also a command-line tool that takes PNG or JPEG images as input to produce JPEG files.

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).

libheif is an ISO/IEC 23008-12:2017 HEIF and AVIF (AV1 Image File Format) file format decoder and encoder.

OpenSlide is a C library for reading whole slide image files (also known as virtual slides). It provides a consistent and simple API for reading files from multiple vendors.

Steghide is a program to `hide' data in various kinds of image and audio files. This practice is known as steganography, but the method used by steghide is not very secure and should not be used where security is at stake. Even if a password is used, steghide offers little plausible deniability.

Nonetheless, neither color nor sample frequencies are changed, making the embedding resistant against first-order statistical tests not aimed specifically at this tool.

Mtpaint is a graphic editing program which uses the GTK+ toolkit. It can create and edit indexed palette or 24bit RGB images, offers basic painting and palette manipulation tools. It also handles JPEG, JPEG2000, GIF, TIFF, WEBP, BMP, PNG, XPM formats.

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.

Zimg implements the commonly required image processing basics of scaling, colorspace conversion, and depth conversion. A simple API enables conversion between any supported formats to operate with minimal knowledge from the programmer.

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.

Libjpeg implements JPEG image encoding, decoding, and transcoding. JPEG is a standardized compression method for full-color and gray-scale images. It also includes programs that provide conversion between the JPEG format and image files in PBMPLUS PPM/PGM, GIF, BMP, and Targa file formats, as well as lossless JPEG manipulations such as rotation, scaling or cropping:

1. cjpeg

2. djpeg

3. jpegtran

4. rdjpgcom

5. wrjpgcom

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.

Gifsicle is a command-line GIF image manipulation tool that:

• Provides a batch mode for changing GIFs in place.

• Prints detailed information about GIFs, including comments.

• Control over interlacing, comments, looping, transparency, etc.

• Creates well-behaved GIFs: removes redundant colors, only uses local color tables, etc.

• Shrinks colormaps and change images to use the Web-safe palette.

• Optimizes GIF animations, or unoptimizes them for easier editing.

Two other programs are included with Gifsicle: gifview is a lightweight animated-GIF viewer, and gifdiff compares two GIFs for identical visual appearance.

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.

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

PerceptualDiff visually compares two images to determine whether they look alike. It uses a computational model of the human visual system to detect similarities. This allows it too see beyond irrelevant differences in file encoding, image quality, and other small variations.

Libpng is the official PNG (Portable Network Graphics) reference library. It supports almost all PNG features and is extensible.

OpenJPH is an implementation of HTJ2K, also known as JPH, JPEG2000 Part 15, ISO/IEC 15444-15, and ITU-T T.814.

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.

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.

JPEG XR is an approved ISO/IEC International standard (its official designation is ISO/IEC 29199-2). This library is an implementation of that standard.

FreeImage is a library for developers who would like to support popular graphics image formats like PNG, BMP, JPEG, TIFF and others.

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.

This package contains a reference implementation of JPEG XL (encoder and decoder).