Yes, as you guessed right the images are of same field-type as the avatars.
There are still small particularities, but most is same.
And it's a good catch that they behave differently of other field-types (blank on empty).
It works as intended, so not a bug.
However, consistency improvement could be made here...
EDIT: marked #134
Post edited by: beat, at: 2008/12/13 18:50