Wu once served in Hsiachiu, Yenchou, as a district magistrate in charge of the prison and the police. There on the wall of an earthen building beside a bridge, he is said to have painted a hundred horses which, as soon as the picture was completed, leapt off the wall, dashed over the bridge, and disappeared. From then on, the bridge was called the Bridge of the Painted Horses.
他曾在兗州瑕丘當縣尉，主管典獄捕盜；由於藝術境界本得之於性情，並非積習所能達到的，相傳他曾在一橋旁土屋壁上畫馬百匹，畫畢，馬破壁而出，過橋逸去，所以這座橋又被稱為「畫馬橋」。