auto launch app is not yet possible, but i could ask it, it has been discussed before.
however you can configure other programs to launch and work on the file using the Extrernal Tool configuration, and then launch them through the menu manually.
Auto rotate - i could add it.
I'm starting more and more to think we might need a little script system for specifying actions to perform on captore (or a menu of them), which could include cropping, shadows, borders, resizing, rotation, etc.
as far as transparent corners.. i'll look into it.