XnConvert
ImBatch
DVDVideoSoft Image Convert and Resize
Batch Image Resizer
Phatch
Ralpha Image Resizer
Fotosizer
FastStone Photo Resizer
FastStone MaxView
JPEGView
XnView MP
IrfanView
FastStone Image Viewer
splash image viewer
Artsage
ImageGlass
XnConvertImBatch - ImBatch is a batch image processor with a nice graphical user interface.
JPEGView - JPEGView is a small and fast viewer/editor for JPEG, BMP, PNG, GIF and TIFF images.
DVDVideoSoft Image Convert and Resize - Free Image Convert and Resize is a compact yet powerful program for batch mode image processing.
XnView MP - XnView is a free software that allows you to view, resize and edit your images. It supports more than 500 different formats!
Batch Image Resizer - Resize, crop, shrink, flip, exif-rotate, convert, enhance, process multiple pictures and photos with professional software! 120+ Actions, 30+ Image Formats
IrfanView - IrfanView ... one of the most popular viewers worldwide.