I think I might know where you're coming from. Why give the user the chance to preview their own image un-bordered when they should already know what the image looks like without it anyway. I think, whilst a valid and agreeable point, the need to switch between a rendered and non-rendered image is important for the decision whether to keep the border or not.
Agreed. And yes that's a logical thing to do, to be able to see the original... ok, sorry sabrown.
But just one thing, can you put a checkbox that would override the rendering process or make so fast (by drawing nothing) that would be un-noticable?