Image compression codecs should be adapted to the practical reality that most images are first viewed as thumbnail images, before the full size image is accessed. Existing JPEG variants, progressive and hierarchical, could be used for thumbnail based image access, but would involve a total re-engineering of existing libraries. An alternate proposal is made for a new variant of JPEG coding based on a reversible transformation of the JPEG output of existing compilers, so that existing decoder/encoders can be utilized, and existing JPEG libraries can be modified with no alteration to the quality of full size images after decompression. In the proposed scheme, the image code is partitioned into a thumb part and the remainder, or FF part. The thumb part is sufficient for the production of an image thumbnail, while this partition of the code together with the FF partition is required for full featured image reconstruction.