PhotoFiltre is a Free Photo Editing program with a great deal of features and is perfect for the average home user with a digital camera. It doesn't have CMYK support or the ability to work in Layers but it has almost everything else including Batch file support, allowing you to apply effects and Transformations to all selected files in a folder. The Program has a simple interface and a huge range of Tools available as you can see below.
The program contains some really useful filters, just have a look at the selection below, each Catagory having its own options and filters.
A couple of transformations and Filters and I created the button on the Left.
Give the program a try you won't be dissapointed. I use it all the time because it's fast to load, easy to use and has some of my favourite Photo Editing Functions.