In September 2015, Ms. Abo Rebieh got a call from an activist friend asking her to meet at a cafe. It was a trap: When she arrived, security was waiting.

Ms. Abo Rebieh, a member of the educated middle class, found herself imprisoned with women who were barely literate, and mostly arrested at random. She became a kind of spokeswoman and sounding board, conveying their needs and requests to guards and helping them talk through experiences.

Her art then became a mirror for fellow prisoners who had none: She drew them so they could see themselves. She drew them all in shaded black and white, their grimacing faces and thin limbs influenced by one of her favorite artists, Goya.

Ms. Abo Rebieh was released in 2016, but her case was still open. She fled to Lebanon, where she is stuck because she is still wanted in Syria. Last year, she won an art residency in Spain, to study Goya and paint Syria’s ghosts as an echo of his. But the Spanish government denied her a visa.