For want of not hijacking but I give one away for free that automatically detects the size of the images you're working on (and they don't have to be power 2 images) and runs the transitions based on that. Also you can just put as many grey scale transitions images in the folder and it'll use them, and it comes with 16 defaults too after all not everyone wants perfectly linear transitions, scribbled transitions look much more natural.
It might not be as friendly but it's free.
It might not be as friendly but it's free.