In this paper, we present a procedural 2.5D water flow simulation technique to animate pictures. For a given picture, we convert it into a 2.5D structure and then perform water simulation for the 2.5D structure (like a shallow-relief sculpture). The proposed approach is divided into three phases: image processing, water simulation and rendering. First, we extract the objects in the picture and compute their 2.5D structure based on image processing techniques. Second, a procedural based approach is adopted to simulate water flows over the 2.5D structure. Finally, we apply a simple ray tracer to render final images. Experimental results show that the simulated water flows naturally over the 2.5D structure of the pictures at real time rates. We also printed out the 2.5D structures of the virtual objects as 3D models for visual comparison.