A new effective mechanism is proposed for the browsing of large compressed images over the Internet. The image is compressed with the JPEG 2000 into one single bitstream and put on the server. During the browsing process, the user specifies a region of interest (ROI) with certain spatial and resolution constraint. The browser only downloads the portion of the compressed bitstream that covers the current ROI, and the download is performed in a progressive fashion so that a coarse view of the ROI can be rendered very quickly and then gradually refined as more and more bitstream arrives. In the case of the switch of ROI, e.g., zooming in/out or panning around, the browser uses existing compressed bitstream in cache to quickly render a coarse view of the new ROI, and in the same time, request a new set of compressed bitstream corresponding to the updated view. The system greatly improves the experience of browsing large images over the slow networks.