Rather tricky, without much context. So, I have three main hunches of mine:
Nem tantas fotos quanto eu poderia, mas então (em compensação, talvez?) fiz muitos amigos.
Perhaps it meant he/she is "in peace with th at", he/she can live with that. That is, okay just the same.https://www.wordnik.com/words/pax
n. Friendship, or a friend; -- esp. in the phrases to make pax with, to make friends with, to be good pax, to be good friends; also, truce; -- used esp. interjectionally.
The third would be (this one, you can see intersects with the first meaning, one is giving a "truce" to him/herself:
-Not as many photos as I could have, but pax.
-Not as many photos as I could have, but let´s give it a slack.
-Not as many photos as I could have, but, well it´s not the end of the world.
-Not as many photos as I could have, but why should I be so worried about it? (I was on my holidays, after all...!)