Option 1
The password is communicated independent of the image.
Necessary to understand relationship b/w sender/receiver.
anon → anon?
whitehat → whitehat?
whitehat → anon?
blackhat → blackhat?
Option 2
A clue to the password is contained in the image/filename/properties.
Possible to guess after inferring relationship (see Option 1)
Option 3
The password and presence of steno is contained in the image.
Consider patterns
Consider content of image
Consider context of posts
What's the best avenue here?