When I import my photos to Preview, I use my Nik D80 as a hard drive and just drag the current folder over to the desktop. Then I fanny about a bit with the photos, sharpening up, using the auto white balance and then when I come to quit out of Preview, I save my photos. Then when I go back to look at them, there are light blue parallel lines on the photos. Some of the photos have them, some of them dont. I am going to try experimenting with my process, but has anyone experienced this before. MacBook black with 2Gb ram (normal spec otherwise) Nikon D80 camera with 2Gb memory card USB cable. Its not a crucial, as I photograph buildings and still lifes, so they are not going anywhere and I can take them again, but its just puzzling. Thank you for any help given all the best D.