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.