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.

This is a tiny, header-only C++ library for manipulating INI files.

This package provides a C interface to the VIGRA C++ computer vision library. It is designed primarily to ease the implementation of higher-level language bindings to VIGRA.

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.

MyPaint is a simple drawing and painting program that works well with Wacom-style graphics tablets.

This package provides a library for the QOI image format, offering fast, lossless image compression.

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

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.

LibSIXEL is a an encoder/decoder implementation for DEC SIXEL graphics, and some converter programs. SIXEL is one of image formats for printer and terminal imaging introduced by DEC. Its data scheme is represented as a terminal-friendly escape sequence. So if you want to view a SIXEL image file, all you have to do is cat it to your terminal.

Simple encoder and decoder for blurhashes. Contains a command line program as well as a shared library.

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

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.

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

Nifti_clib is a set of I/O libraries for reading and writing files in the nifti-1, nifti-2, and (to some degree) cifti file formats. These are binary file formats for storing medical image data, e.g. MRI and fMRI brain images.

libyuv is an open source project that includes YUV scaling and conversion functionality. It can:

• Scale YUV to prepare content for compression, with point, bilinear or box filter.

• Convert to YUV from webcam formats for compression.

• Convert to RGB formats for rendering/effects.

• Rotate by 90/180/270 degrees to adjust for mobile devices in portrait mode.

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.

libspng is a simple C library for loading Portable Network Graphics (PNGs), intended as an easy-to-use replacement for libpng.

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.

OpenJPEG is an implementation of JPEG 2000 codec written in C language. It has been developed in order to promote the use of JPEG 2000, a still-image compression standard from the Joint Photographic Experts Group (JPEG). Since April 2015, it is officially recognized by ISO/IEC and ITU-T as a JPEG 2000 Reference Software.

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

GGG (Guile Glyph Generator) is a command-line utility that allows you to generate pretty images/badges which can be used for your projects, announcing tech used, sponsoring and appreciating other projects, distinguishing versions of things supported, etc.

GGG is highly configurable, reads Scheme files where you define your tasks, and supports badges between one and three parts. It leverages SVG generation from Lisp and S-expressions, building pixel perfect badges.

Jp2a is a small utility that converts JPEG images to ASCII.

Libtiff provides support for the Tag Image File Format (TIFF), a format used for storing image data. Included are a library, libtiff, for reading and writing TIFF and a small collection of tools for doing simple manipulations of TIFF images.

Leptonica is a C library and set of command-line tools for efficient image processing and image analysis operations. It supports rasterop, affine transformations, binary and grayscale morphology, rank order, and convolution, seedfill and connected components, image transformations combining changes in scale and pixel depth, and pixelwise masking, blending, enhancement, and arithmetic ops.