TortoiseIDiff
Depending on your project, not all files which are under version control are text files. Most likely you will have images too, for example screenshots and diagrams for the documentation/helpfile.
For those files it's not possible to use a common file diff tool, because they only work with text files and diff line-by-line. Here is where the Tortoise Image Diff tool (TortoiseIDiff) comes to the rescue. It can show two images side-by-side, or even show the images over each other alpha blended.
