XnView is a popular Windows image editor that has now been ported to Pocket PC and Smartphone, allowing you to tinker around with your pictures while you're on the move.
The app is designed to help you view, manage and modify all the photos stored on your mobile phone. Considering it's a mobile application, it's surprising just how much you can do with this version of XnView. You can display images one-by-one, create elegant slideshow presentations with transitions, organise them into different folders, share them friends via IR, Bluetooth or email, and even capture your mobile screen as an image.
One of the great things about XnView is the sheer number of ways it lets you view your pictures. There are five different viewing modes - Thumbnail, List, Detail, Filmstrip and Full Screen. The buttons for navigating folders are clearly-labelled and easily accessible, and you can access all the Exif data and use it to categorise your pictures.
The program includes a number of basic editing features, though these are not powerful or advanced enough to do anything too creative.
But if you're looking for a way of managing your mobile photos on the fly, they don't come much better than XnView.