Progressive image transmission (PIT) is useful in Web applications. When the network bandwidth is restricted, the user can preview a coarse version of the image to decide if the entire detail of a picture needs to be transmitted. We propose a newly developed mechanism for PIT. According to the continuity of image pixels, we introduce a guessing-by-neighbors strategy. Only half of the original pixels are transmitted, with additional pixels for error recovery from unsuccessful guessing. The proposed algorithms can be used for both gray-level and color pictures. Bandwidth is saved. The preliminary results show that the number of transmitted bits is reduced in the first few rounds. Additionally, the PSNR values in the first few rounds are much better than other PIT techniques.