I am not here to advocate the usage of particular programs but I can only recommend you FastStone if you’re looking for a free replacement of your current image viewer. One reason for that...
ACDSee is one of the most popular commercial image viewers (and more) on the market. You can squeeze more out of it via these keyboard shortcuts.
If you do not need more than a basic photo viewer you can just as well settle with Windows Picture and Fax Viewer which ships with Windows OS. Here is its shortcut key list.
Irfan View is one of the most popular freeware image/graphic viewers . Bellow is the full list of keyboard shortcuts :