Überzug is a command line util which draws images on terminals by using child windows. The advantages of using Überzug are:

• No race conditions as a new window is created to display images.

• Expose events will be processed, so images will be redrawn on switch workspaces.

• Tmux support (excluding multi pane windows).

• Terminals without the WINDOWID environment variable are supported.

• Chars are used as position - and size unit.

• No memory leak (/ unlimited cache).

lsix lists the images in a directory by displaying their thumbnails. Images are displayed in sixel graphics. lsix automatically detects terminal features and adapts the output to offer the highest quality possible. It can usually display non-bitmap graphics, including PDF. Your terminal should be sixel capable, like xterm -ti vt340.

Qimgv is a configurable Qt image viewer, with optional video support.

Swayimg is a fully customizable and lightweight image viewer for Wayland based display servers. It supports the most popular image formats (JPEG, JPEG XL, PNG, GIF, SVG, WebP, HEIF/AVIF, AV1F/AVIFS, TIFF, EXR, BMP, PNM, TGA, QOI, DICOM, Farbfeld). It has fully customizable keyboard bindings, colors, and many other parameters. It also supports loading images from files and pipes, and provides gallery and viewer modes with slideshow and animation support. It also includes a Sway integration mode: the application creates an overlay above the currently active window, which gives the illusion that you are opening the image directly in a terminal window.

sxiv is an alternative to feh and qiv. Its primary goal is to provide the most basic features required for fast image viewing. It has vi key bindings and works nicely with tiling window managers. Its code base should be kept small and clean to make it easy for you to dig into it and customize it for your needs.

MComix is a customizable image viewer that specializes as a comic and manga reader. It supports a variety of container formats including CBZ, CB7, CBT, LHA.

For PDF support, install the mupdf package.

Geeqie is a lightweight GTK+ based image viewer for Unix like operating systems. It features: EXIF, IPTC and XMP metadata browsing and editing interoperability; easy integration with other software; geeqie works on files and directories, there is no need to import images; fast preview for many raw image formats; tools for image comparison, sorting and managing photo collection. Geeqie was initially based on GQview.

imv is a command line image viewer intended for use with tiling window managers. Features include:

• Native Wayland and X11 support.

• Support for dozens of image formats including:

  • PNG

  • JPEG

  • Animated GIFs

  • SVG

  • TIFF

  • Various RAW formats

  • Photoshop PSD files

• Configurable key bindings and behavior.

• Highly scriptable with IPC via imv-msg.

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.

imgp is a command line image resizer and rotator for JPEG and PNG images. It can resize (or thumbnail) and rotate thousands of images in a go while saving significantly on storage.

This package may optionally be built with python-pillow-simd in place of python-pillow for SIMD parallelism.

Libicns is a library for the manipulation of Mac OS IconFamily resource type files (ICNS). icns2png and png2icns are provided to convert between PNG and ICNS. icns2png will extract image files from ICNS files under names like "Foo_48x48x32.png" useful for installing for use with .desktop files. Additionally, icontainer2png is provided for extracting icontainer icon files.

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

JBIG2 is designed for lossy or lossless encoding of bilevel (1-bit monochrome) images at moderately high resolution, and in particular scanned paper documents. In this domain it is very efficient, offering compression ratios on the order of 100:1.

This is a decoder only implementation, and currently is in the alpha stage, meaning it doesn't completely work yet. However, it is maintaining parity with available encoders, so it is useful for real work.

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.).

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

pngquant is a PNG compressor that significantly reduces file sizes by converting images to a more efficient 8-bit PNG format with alpha channel (often 60-80% smaller than 24/32-bit PNG files). Compressed images are fully standards-compliant and are supported by all web browsers and operating systems.

Features:

1. High-quality palette generation using a combination of vector quantization algorithms.

2. Unique adaptive dithering algorithm that adds less noise to images than the standard Floyd-Steinberg.

3. Easy to integrate with shell scripts, GUIs and server-side software.

4. Fast mode for real-time processing/large numbers of images.

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.

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.

Converseen is an image batch conversion tool. You can resize and convert images in more than 100 different formats.

The libUEMF library is a portable C99 implementation for reading and writing WFM, EMF, and EMF+ files.

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.

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.

libimagequant is a small, portable C library for high-quality conversion of RGBA images to 8-bit indexed-color (palette) images. This library can significantly reduces file sizes and powers pngquant and other PNG optimizers.

jhead is a simple command line tool for display and manipulate EXIF header data embedded in JPEG images.