Recover deleted photos on macbook air
I used a trial version of a software product that was meant to delete multiple files and photos on my macbook air. Now when I go to iPhoto both identical photos initially appear but then within less than a second the photo disappears and in it's place is the grey background with a dashed white line where the edge of the photo used to be. When I click on the enclosed area it expands as if there was a photo there but all I get is a black background with a grey caution mark in the middle. How can I restore my photos?
MacBook Air, OS X Mountain Lion (10.8.2)