Two weeks after he won first prize in the 2012 World Press Photo contest, French photojournalist Rémi Ochlik was killed by rocket fire during a Feb. 22 military assault on the town of Homs, Syria. He was 28.

Ochlik's passion for photography began when his grandfather gave him an Olympus OM-1 film camera. After graduating from high school, he went to Paris to study photography at...