NeonView is a minimalist, lightweight image viewer written in C and GTK, completely free and open-source, created by TuxArena. Since it was recently launched, NeonView includes only a handful of features, but this is the base for development of new features and functionality.
The goal of NeonView is to stay lightweight while also providing ease of use and only the necessary options a basic image viewer should have.
NeonView is written in C and using the GTK+ toolkit, version 2.24. It was tested in Ubuntu 11.04 so it should work without issues on any distribution using a current version of GTK+ 2.
 
The features of NeonView:
it supports many image formats, including JPG, PNG, SVG, GIF or TGA (any format supported by gdk_pixbuf) clean and easy-to-use interfacezoom in/zoom outrotate left/right, flip imageeasy to use keyboard bindings provides configuration window for several usability features can remember fit to window option over sessions allows navigation with next/prev buttons with images sorted by name fit to window or normal size image view modesit remembers the window size between sessions and can be started maximized it allows manual configuration via ~/.neonview/neonview.cfg
Download.
There are two packages available for NeonView. You will only need the first one to run NeonView, while the second one contains the source code:
NeonView 0.6.0 – Binary
To run the program just double-click the neonview executable.
NeonView 0.6.0 – Source Tarball
To compile NeonView type make inside the neonview-0.6.0-src directory.
 
Screenshots.
NeonView 0.4.0 ‘Corydoras’
The main window

The configuration window

The about and manual windows

NeonView 0.2.0 ‘Betta splendens’