I have a 24" 2010 iMac running OS 10.5.8. I'm using photos in iPhoto as the screensaver & some are blurred. I read that all the photos must be in the same format, .jpeg for example, but I can't track the problem much beyond there. Several questions: 1. Is there an easy way to change photos in other formats like .bmp into .jpeg, using my iMac? 2. Must all the photos in all the different albums be the same format, or can the photos in one album be .jpg, another album have .bmp, etc.? 3. The photos are different sizes, some tiny and others big. Is there an ideal size where all the photos will be clear, i.e. 900X800? I've noticed the blurred photos are smaller than 500X300. 4. Is there an easy way to change the photos to be the ideal size, considering some of the photo albums have 150 pictures? I dread going thru each picture changing the size. I'd appreciate any helpful answers. Thanks, Joe.