Macbook Pro retina. Yosemite. iPhoto 9.6 I have a problem with iPhoto. When looking at my photos it shows the thumbnails OK. But when I go to show the photo I want, it shows it zoomed in to the max, and I can't zoom out ( or pan around the zoomed image ). Is this a know issue? And what could be the fix? Would it help to delete the pref files - if so which files would I delete? Thanks for any help on this.