High Efficiency Video Coding (HEVC), the latest international standard of video coding under development, has shown a major breakthrough with regards to compression efficiency. But most of the currently published studies were intended to evaluate the overall R-D performance of HEVC in comparison to prior H.264/AVC video coding standard. In this paper, we present sufficient rate-distortion performance comparisons of image coding between the HEVC and previous image and intra-only video coding standards, including JPEG 2000, JPEG LS and H.264/AVC intra high profile. In addition, some recently reported performances of HEVC are also reviewed and compared. The coding simulations are conducted on a set of recommended video sequences during the development of the HEVC standard. Experimental results show that HEVC can offer consistent performance gains over a wide range of bitrates on natural video sequences as expected. Besides, we also present the comparison results of all these standards in the scenario of lossless image coding.