Photo viewing in preview help

Im having problems with the permissions of viewing. I got a library of manga that i was reading and im halfway through. Everything was going fine but then when i tried to open more manga (i read them through preview since its just picture scans) it came up with a message saying i dont have permission and that i should go to file>get info. I do that and i see sharing and permissions, it has three - me (admin), staff and everyone. All of them say read & write. I go online and it tells me to go and look at ownership and permissions but i cant find that. Ive also repaired and verified disk permissions through disk utility. I dont know what else to do. HELP!!!