NeonView is described as 'minimalist, lightweight image viewer written in C and GTK, completely free and open-source, created by TuxArena' and is an app in the Photos & Graphics category. There are more than 25 alternatives to NeonView for a variety of platforms, including Windows, Linux, Mac, Xfce and PortableApps.com. The best alternative is IrfanView. It's not free, so if you're looking for a free alternative, you could try JPEGView or Preview. Other great apps like NeonView are XnView MP (Free Personal), XnView (Free Personal), Imagine (Free) and Eye of GNOME (Free, Open Source).
Imagine is an Image & Animation Viewer for Windows with screen capture function. Features - View and save image/animation files with very fast speed - Support for numerous image/animation file formats: GIF, BMP, PNG, JPG, TIF, TGA, PCX, ICO, ANI, FLI, and many more...
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.
QuickViewer is a graphic image viewer for comfortable browsing of many images. This software performs reading of image data in advance. And drawing the imported image data on the screen with OpenGL. You can browse images with much smoother response than ever before.