What is your phone model? I'll have a look and try to release an update. You can use any UK banknote.
(aside: one would expect a picture taking using camera app to be fairly trivial, but it is actually very challenging on Android, where each vendor implements it with its own little subtleties)
(aside: one would expect a picture taking using camera app to be fairly trivial, but it is actually very challenging on Android, where each vendor implements it with its own little subtleties)