XnView MP - XnView is a free software that allows you to view, resize and edit your images. It supports more than 500 different formats!
IrfanView - IrfanView ... one of the most popular viewers worldwide.
nomacs - nomacs is a free, open source image viewer, which supports mu
Seer - A Windows Quick Look Tool in Qt.
FastStone Image Viewer - FastStone Image Viewer is a fast, stable, user-friendly image browser, converter and editor.
Eye of Gnome (eog) - Simple image viewer for the GNOME desktop.