A low complexity spatial-domain error concealment method is proposed to reconstruct still images and intra-coded (I) frames in video when they are transmitted through unreliable channels in this work. The proposed concealment algorithm works with the following steps. First, missing edges in a lost macroblock (MB) are detected and recovered using gradient data. Then, the lost MB is implicitly divided into several segments along the recovered edges. Finally, each pixel in a segment is directionally interpolated from boundary pixels adjacent to the segment. Experimental results show that the proposed algorithm can recover high as well as low frequency information in lost MBs and provide better visual quality in comparison with the conventional spatial domain interpolation.