As Brian Otieno was waiting to start college six years ago, he spent his days snapping pictures with his phone as he wandered the unpaved streets and alleyways of Kibera, a sprawling shantytown on the outskirts of Kenya’s capital, Nairobi. Often referred to as Africa’s largest slum, Kibera is home to up to a million people living side by side in ramshackle homes. Poverty, crime and hardship have long defined its visual narrative.

Mr. Otieno, who had grown up in Kibera, saw beyond those stark realities.

“I would look around me, at the rooftops and the scenery, and it just looks beautiful,” he said. “And I would think this view is amazing for photography.”