I am a photographer trying build a portfolio website. I want my pictures to be as large as possible for the screen on which they are viewed. I am using Flash Catalyst CS 5.5 with Mac OS X Lion. The problem I am facing when using the new constraint feature is that the aspect ratio of the pictures changes based on the size of browser. How can I have the photos maintain a consistent aspect ratio while still growing/shrinking with the size of the screen/browser?