In this paper, we present a novel content-based image error detection and error concealment algorithm to improve the image quality degraded during its transmission over wireless channel. The damaged image blocks are detected by exploring the contextual information in images, such as their consistency and edge continuity. The statistical characteristics of missing blocks are then estimated based on the types of their surrounding blocks (e.g., smoothness, texture and edge). Finally different error concealment strategies are applied to different types of blocks in order to achieve better visual quality. Instead of assuming random errors in packets, we simulate the errors of wireless channel based on the Rayleigh model. Simulation results demonstrate that our proposed method is effective in terms of visual quality assessment and efficient in terms of computation complexity.