Lion Photobooth Pictures
If you're in the Open File dialog box, there is a heading in the sidebar that says "Media". Under that heading is an entry for Photos. Click that, and then at the top of the dialog, it will show any iPhoto albums you have. But, if you scroll down to the bottom, you can select "Photo Booth", and you should be able to load all your photo booth pictures from there. Unless I'm missing something, that should be all you need.