The China Space News Agency published an image showing the Chinese Mars rover and lander in the same photograph.
What camera took the picture?
The group picture was taken by a wireless camera that had been released by the rover on the ground, from its bottom side. See this article in Chinese: http://www.cnsa.gov.cn/n6758823/n6758838/c6812123/content.html and use the Automatic Translator.
I believe the explanation in Chinese reads:
"The picture of the "touring group" was taken after the rover traveled about 10 meters south of the landing platform, released the separate camera installed at the bottom of the vehicle, and then retreated in the vicinity of the landing platform. The separate camera took pictures of the movement of the rover and the photo of the rover and the landing platform. The image was transmitted to the rover through wireless signals, and then relayed back to Earth by the rover through the orbiter."