1. A method of compressing an image, the method comprising: grouping member entities of the image into a plurality of groups based on each image features, each of the plurality of groups including member entities sharing common features; selecting at least one group representative from at least one of the plurality of groups; estimating final control parameters for each of the group representatives in an iterative manner; and compressing the image based on the estimated final control parameters, wherein estimating the final control parameters comprises: estimating a resulting file size of the image; comparing the estimated file size with a pre-defined minimum file size; and computing the final control parameters if the estimated file size is less than or equal to the minimum file size.