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.

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.

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.

ytfzf is a POSIX script that helps you find PeerTube or YouTube videos without requiring API and opens/downloads them using mpv/ytdl.

Viewnior is an image viewer program. Created to be simple, fast and elegant. Its minimalistic interface provides more screenspace for your images. Among its features are:

1. Fullscreen & Slideshow

2. Rotate, flip, crop, save, delete images

3. Animation support

4. Browse only selected images

5. Navigation window

6. Set image as wallpaper (Gnome 2, Gnome 3, XFCE, LXDE, FluxBox, Nitrogen)

7. Simple interface

8. EXIF and IPTC metadata

9. Configurable mouse actions

The hydrus network client is an application written for internet-fluent media nerds who have large image/swf/webm collections. It browses with tags instead of folders, a little like a booru on your desktop. Advanced users can share tags and files anonymously through custom servers that any user may run. Everything is free and privacy is the first concern.

feh is an X11 image viewer aimed mostly at console users. Unlike most other viewers, it does not have a fancy GUI, but simply displays images. It can also be used to set the desktop wallpaper. It is controlled via commandline arguments and configurable key/mouse actions.

qView is a Qt image viewer designed with visually minimalism and usability in mind. Its features include animated GIF controls, file history, rotation/mirroring, and multithreaded preloading.

This package provides a user-friendly terminal image viewer that uses graphic capabilities of terminals (Sixel, Kitty or iterm2), or 24-Bit color capabilities and unicode character blocks if these are not available.

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.

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).

Catimg is a little program that prints images in the terminal. It supports JPEG, PNG and GIF formats.

gpicview is a lightweight GTK+ 2.x based image viewer. It is the default image viewer on LXDE desktop environment.

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.

grim can create screenshots from a Wayland compositor.

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

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

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

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

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.

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.

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.

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.

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.