Ezthumb - A video thumbnail generator based on ffmpeg.
digiKam - Professional Photo Management with the Power of Open Source
Auto-Movie-Thumbnailer - AMT - Auto-Movie-Thumbnailer v11 THE Batch Movie ScreenCap Creator... Create ScreenCaps of - any number of movies, - located anywhere on your computer, -
XnView MP - XnView is a free software that allows you to view, resize and edit your images. It supports more than 500 different formats!
MoviePrint - MoviePrint lets you create screenshots of entire movies in an instant.
FastStone Image Viewer - FastStone Image Viewer is a fast, stable, user-friendly image browser, converter and editor.