There are alternatives to using Sony Vegas for Stopmotion. Vegas can be used for stop motion I guess, but you can always get a stopmotion program like Stopmotion Pro or Stopmotion animator. Just Google search it.

and if you import the finished render into Vegas, you could prolly add the post effects there..

...Hmm, havent tried this, but try clicking the first, shift clicking the last (Which selects all of them) and try resizing one and see if it applies it to all... Like I said, havent tried this, but maybe... >_>