Rapid throughput of still image compressed data (e.g. JPEG) is achieved
for presentation of images in rapid succession for browsing or browsing
by panning within large images by using a hardware decoder adapted for
presentation of moving images to reduce the processing load which must be
performed in accordance with software although the still image data is
incompatible with still image data in many respects; some of which
necessarily lead to a loss of image fidelity. The still image data is
partially decoded (e.g. entropy decoded) in software processing and
re-encoded and reformatted to a form which can at least be accepted by
the hardware decoder even though not compliant with any particular moving
picture data standard (e.g. MPEG). Storage in the hardware decoder is
reallocated to provide, in combination with a reduction of slower
software processing, a throughput increase of four-fold or more. Software
processing of the still image data is also allowed to proceed and the
result substituted for the result of the hardware decoding if a given
image is viewed for a time sufficient for the software image processing
to be completed.