Actually there's some solid research behind this. If I recall correctly, people naturally find it much easier to remember which parts of a picture to hit rather

Actually there's some solid research behind this. If I recall correctly, people naturally find it much easier to remember which parts of a picture to hit rather than remembering a password. Unfortunately, I can't find the research and sample that I remember reading about a while back--Google is spammed with Windows 8 stuff when I search for it and I'm terminally lazy. However, I definitely recall reading about research in this vein.