RequirementsThe Joker unlocked - unlocked from level 1
Batman unlocked - unlocked after completing level 12
This can be done during your story progression on level 12, or at any other time after this in the hub area or while replaying a level.
AchievementOnce in hub hold the

button to bring up the character selection screen now:
Scroll across 14 tokens on the first row for Batman
Change to your second playable character by tapping

Once again hold

for character selection, scroll down to the 4th row and 10th token across and select the Joker.
Now being in control of the Joker stand near Batman then, tap

to go into Selfie mode move the left analogue so both are in image and press

to take photo.
Sorry, this Game Clip has been removed
As soon as pressed pop achievement unlocked.
Congratulations!
Happy Hunting