Nomacs 2.4.6 recently released, is a free image viewer for windows, linux, and mac systems. Nomacs is small, fast and able to handle the most common image formats including RAW images. Additionally it is possible to synchronize multiple viewers. A synchronization of viewers running on the same computer or via LAN is possible. It allows to compare images and spot the differences (e.g. schemes of architects to show the progress), zoomable grid preview of thumbnails, change transparency of windows and many other nice features.