To get the more dynamic shots, you need to use AR+. Not every phone can handle it though, but fortunately it's not required to get Smeargle. Best you can do in normal AR mode is tapping on the pokemon to get it to attack.
For Smeargle, just keep taking photos while keeping an eye on the thumbnail in the bottom right-hand corner. Eventually, he'll appear with the thumbnail pulsing three times. Look at the image properly, then exit to the map and he'll spawn in the wild.