So I imported all my photos into iPhoto, but I am having a small problem. In one particular roll, the image thumbnails show up as dotted boxes. I tried re-importing, but the problem still persisted with only that particular roll. The images are there because when I double-click on the image I am able to see it, and one-click enhance it, but when I try to manual adjust the brightness, contrast, etc. the image goes completely black... Any idea on what´s going on? Thanks in advance.