A quality level determining the extent to which each image file is compressed is automatically computed for each image file in a set to ensure that the total size of the compressed image files does not exceed a predefined limit. The compressed size of each image file is initially determined when compressed at a predefined minimum acceptable level and at a nominal level. The relative complexity of the image files is determined based upon their high frequency energy content. As a function of the image file complexity, and starting with the compressed sizes initially determined, the appropriate quality level is determined for compressing each of the image files in an iterative process that ensures the total size of the compressed image files does not exceed the predefined limit, while retaining acceptable quality. Thus, a set of image files can be compressed optimally to fit within a limited storage.