Adapter - Adapter is freeware (100% free software). Unlike other free apps, Adapter is lightweight and comes with a completely spam free installer that doesn't install toolbars or gunk up your computer. Adapter won't add obnoxious watermarks to your output.
ImBatch - ImBatch is a batch image processor with a nice graphical user interface.
HandBrake - HandBrake allows users to easily convert video files into a wide variety of different formats.
DVDVideoSoft Image Convert and Resize - Free Image Convert and Resize is a compact yet powerful program for batch mode image processing.
Any Video Converter - Any Video Converter is an All-in-One video converting tool with easy-to-use graphical interface, fast converting speed and excellent video quality. It allows you to effortlessly convert video files between every format!
Batch Image Resizer - Resize, crop, shrink, flip, exif-rotate, convert, enhance, process multiple pictures and photos with professional software! 120+ Actions, 30+ Image Formats