FONTENAY-LE-COMTE, France — Najah al-Bukai cannot forget.

As an accomplished artist in Syria before the war, Mr. Bukai had long thought his photographic memory was his greatest asset, allowing him to recreate scenes on his sketch pads and canvases days, months and even years after he witnessed them. But now, after he has survived two stretches in the Syrian government’s notorious detention centers, his sharp memories only serve to haunt him.

One day recently, home with his family in Fontenay-le-Comte, a sleepy city in the Loire valley, he methodically opened boxes containing dozens of drawings he has made of the images burned into his brain. It is the only way he knows of coping with the traumas he witnessed, and suffered, in Syria’s torture chambers.

In one, men wearing only their underwear carry a corpse in what looks like a sheet or blanket, for eventual disposal, Mr. Bukai says, in the back of a truck in a pile of other bodies. He recalls a number, 5535, on the young man’s chest. They had been ordered to strip to their underwear, Mr. Bukai explained, so they could be easily spotted if they tried to escape.

“Art saved me,” he said, while laying the drawings out on a tabletop.

His art reminds many critics of the work of the Slovenian artist and Holocaust survivor Zoran Music — haunting, dark and extremely realistic. In his drawings, some prisoners hang by their hands and others undergo other forms of torture, all while their cellmates eat their meals calmly, desensitized to the displays of inhumanity around them.