To put a logo (or anything) in the corner.
Import your still and place in in a new track above your existing video.
Using the track motion control on the still track, resize the image and move it to where you want it. You can even have it move around the screen if you like by using keyframes.
As for your other question, I dont know. Perhaps there is a script you could download that would do it.
Try
www.vasst.com or
http://vegasusers.com/