Set Resolution

How do I set the resolution of my scene so that when I preview it in unity and package it it will be 650x500?

There is a drop down menu in the upper left hand corner of the Preview window with a label of ‘Free Aspect’. If the resolution is set as a default in the publish settings then it will show up there as a choice.

Well I figured out how to set the resolution for a build to 650x500, but how do I set the resolution for the preview in Unity to that resolution or show safe frames at least?