1. A computer-implemented method comprising: determining a plurality of acceptable loss bounds, each acceptable loss bound being associated with one of a plurality of pixels included in an image; performing, using one or more computing devices, a plurality of compression iterations, each compression iteration including at least one decision regarding a loss of image data, the image data comprising a plurality of symbols respectively stored in a plurality of data blocks, each symbol describing one of the plurality of pixels included in the image; and updating, using the one or more computing devices, an entropy model following each compression iteration, the entropy model describing an entropy associated with one or more of the plurality of data blocks, wherein the updated entropy model reflects altered entropy characteristics of one or more symbols in the image data; wherein the at least one decision regarding the loss of image data is decided, for each compression iteration, based on the entropy model as updated following the previous compression iteration; and wherein a total loss of image data from each data block remains within each of the plurality of acceptable loss bounds respectively associated with each pixel included in the image.