You have to take a dramatic photo (1000 PP). The easy way to get this achievement, is during the Day 4 2:00 AM - Mission Family Feud.
In this mission, a daughter (Lillian) and her mother (Camille) have been separated. You have to bring her to her daughter before take them to the safe house. Don't care about the mission's goal, you only need to meet Lillian.
You can find her in the back of the Fortune City Hotel's roof. To going up, take the elevator in the reception room on the right.
When you're on the roof, go close to her front of you. Hold LT + RB to take your camera. Aim Lillian in the middle of your screen and press X to take a photo. Normaly you should unlock the achievement, if you didn't hit 1000 PP, retry.
This solution is simple and safer than take a photo with Snowflake. I try it without succes, Snowflake catch me or I never got the 1000 PP photo when I captured it.
Here is a video, I made it to help you, enjoy your achievement !