SpReader

SpReader is a simple but powerful image viewer that helps you open and view images in many formats. It can even handle displaying photos from ZIP archives. You can add plugins, folder shortcuts and bookmarks, view images full screen or enlarge them. The main window offers some controls so you can go to the first or last, next or previous photo from the uploaded directory. The CPU and RAM usage is quite low, so it won't put too much strain on your computer.