Viewnior!

XnViewMP is a free software to view, organise, convert graphics and photos files or to create slide show, contact sheet, HTML pages.

nomacs is a free image viewer for windows, linux, and mac systems, which is licensed under the GNU Public License v3. nomacs is small, fast and able to handle the most common image formats including RAW images. Additionally it is possible to synchronize multiple viewers. A synchronization of viewers running on the same computer or via LAN is possible. It allows to compare images and spot the differences (e.g. schemes of architects to show the progress).

JPEGView is a small and fast viewer/editor for JPEG, BMP, PNG, GIF and TIFF images. On-the-fly image processing is provided - allowing to adjust typical parameters as sharpness, color balance, contrast and local under-/overexposure.

Geeqie is a lightweight Gtk+ based image viewer for Unix like operating systems. It was forked from GQview. The development is focused on features for photo collection maintenance: raw format, Exif/IPTC/XMP metadata and integration with programs like UFraw, ImageMagick, Gimp, gPhoto or ExifTool.

Imagine is an Image & Animation Viewer for Windows with screen capture function.

Eye of GNOME is the official image viewer for the GNOME Desktop environment. With it, you can view single image files, as well as large image collections. The Eye of GNOME supports a variety of image file formats. The GdkPixbuf library determines which file formats Eye of GNOME can load and save. If the appropriate plugins are installed on your system, Image Viewer will be able to open more image formats than those listed below.

PhotoQt is a simple, yet powerful and good looking image viewer, written in Qt, published as open-source, and completely free.Photo comes with a variety of features. Most features you would expect from a image viewer should be there.All features of PhotoQt are very easy to use. Should you happen to be confused about some feature, have a look at the settings. Pretty much everything can be adjusted in PhotoQt, and every setting comes with a short explanatory text.

Free Opener allows users to view, edit and print many different types of files without having to download specialty software. Currently, the software supports over 80 different file formats including Microsoft Office Files (.doc, .docx, .ppt, .pptx, .xls, .xlsx, .xlsm, .msg, .vcf), Adobe Files (.swf, .flv, .psd, .pdf), Media files (.avi, .flv, .mid, .mkv, .mp3, .mp4, .mpeg, .mpg, .mov, .wav, .wmv, .3gp, .flac) and many others.

Universal Viewer is an advanced file viewer for wide range of formats. Supported file formats are:

Xee is a lightweight, fast and convenient image viewer and browser. It is designed to be a serious tool for image viewing and management, with a sleek and powerful interface.

Simplistic Image Viewer with focus on speed of rendering and switching between images. A good complement when no editing capabilities are nessesary.