I've seen that picture, and I think it's staged. Consider:
* The child whose diaper can be clearly seen is very obviously 4-6 years old;
* She's running from ... what? There's one tear gas canister or smoke bomb on the ground behind her, but the air around and beyond her is clear;
* She's running from ... what? The several dozen people beyond her are just standing/milling around. Why is she the only one running?
Judging by her arms and her gut sticking out below her top, she's not exactly underfed.
That the Border Patrol deployed tear gas after being pelted by stones is true. It's called self-defense while guarding the border. But that picture looks to be as phony as a $3 bill with Obama's picture on it (everyone knows Clinton is on the $3 bill!).