digiKam - Professional Photo Management with the Power of Open Source
Avogadro - Avogadro is a free, fantastically easy to use molecule editor.
XnView MP - XnView is a free software that allows you to view, resize and edit your images. It supports more than 500 different formats!
ImageJ - and Other Health Care
FastStone Image Viewer - FastStone Image Viewer is a fast, stable, user-friendly image browser, converter and editor.
ACD/ChemSketch - ACD/ChemSketch for personal and academic use brings the power of our structure drawing package to your home computer.