Could be. Makes sense.
As I recall, that picture was taken during a meeting/press conference where POTUS agreed to limited control of automatic weapons. She felt she had been successful in gun control, which her side would probably reward.
MSNBC's Andrea Mitchell just asked, "Is Nikki Haley's departure a sign of things to come at the White House."
This makes a lot of sense other than that she said she was not going to be running in 2020, but time will tell.