To change a picture or directory security level, authenticate yourself as an admin an then simply browse to the picture/directory you want to change the level. You'll see a "Level" field (Ref: C1), please before doing so, check the "Inerithed level", because if the "Inherited Level" is higher or equal to the level you want to set, there is no need to change the level as the picture/directory is already protected (See Understanding Users Level).