Ah! iPhoto 6.0.4 is acting up, and I have no idea what is wrong! Instead of displaying thumbnails of my pictures, it shows squares of dashed lines. The strange thing is that, if I scroll quickly up or down, I can see the pictures for a very short time before they are replaced with the dashed squares. I can, however, view the pictures in slideshows without a problem. What is wrong, and how can it be fixed? I also have trouble with iPhoto in System Preferences--I can use albums as screensavers, but I cannot browse my iPhoto library to select desktop pctures or use entire albums as my desktop. Additionally, I can see file names in the iMovie media-browser, but again I cannot see thumbnails. Please help!