If you take a lot of picture definitely get a micro SD card and save your pict there. Get a higher speed one from a reputable brand.
Depends on how often you take picts your internal phone memory might not be sufficient.
Also if you wiped your phone and forgot to back up the picts saved in the phone memory you will lose them.
The other option is to save the picts in a cloud storage but your data paln might take Big hit depending on your habit
