The present technique selectively handles image data, which is decomposed
into a plurality of resolution levels. The image data may be retrieved in
order of progressively higher resolution levels for display in a
viewport. Initially, the image data may be displayed in the viewport at a
relatively lower one of the plurality of resolution levels. As a user
desires higher resolution displays of all or part of the image, one or
more of the progressively higher resolution levels may be retrieved and
scaled to fit the viewport. Accordingly, the present technique handles
the data more efficiently by accessing the image data in blocks
corresponding to the plurality of resolution levels, rather than
accessing the entirety of the image data. A scaling threshold also can be
used to signal the need for a next higher level of the plurality of
resolution levels.