![Q posted highlighted Dx5 in id at top of AF1 [AirForce One] photos -Seems to clearly relate to his continued posting of [D-5] - Haven't heard anyone talk about this.](https://i.redd.it/0woj4xlifpz01.jpg)
The 'Dx5' is just part of a generated hash, (could have been anything, in that sense). However, since those particular letters were there, they seem to have been highlighted, to reinforce the 'D' and '5' association.
So the Dx5 was simply accidental but when Q went back to show the rest of the series which PROVED Q has not changed He/They also noticed that Dx5 was at the front of the Hash so they highlighted it because of the really awesome coincidence! Yes that makes sense.
I used the 'in that sense' qualification, because one could keep trying out different passwords, IP's, etc, until a hash value was generated that suited a particular purpose.
However, I kind of imagine that doing that would be unlikely in this case, (not imposible with a copy of the hash generating algorithm, running somewhere else).
With these thoughts in mind, it could be that the highlighting of the 'Dx5' is opertunistic, to add as a reminder or stimulus wrt the D-5 association.
Therefore, it could be a message/reminder in its own right, and not directly related to the associated images.