Decompress and load only part of an image?

[b.e.wilson]

I'm working with some very large images, presenting zoomed portions to the viewer (see http://research.uvsc.edu/herbarium/virt ... =00001.jpg).

Is there a way to decompress only a portion of the large .jpg into memory before cropping to save time?

I realize this is an unusual need, but there are many scientific applications (GIS mapping and imagry and botony particularly) where the presentation of large files over the web is essential.

[xnview]

I'm working with some very large images, presenting zoomed portions to the viewer (see http://research.uvsc.edu/herbarium/virt ... =00001.jpg).

Is there a way to decompress only a portion of the large .jpg into memory before cropping to save time?

I realize this is an unusual need, but there are many scientific applications (GIS mapping and imagry and botony particularly) where the presentation of large files over the web is essential.

Currently it's not possible

[b.e.wilson]

I think the "-crop" function of this jpeg addition: http://sylvana.net/jpegcrop/ is what I'm after. It'd be very cool if you could add it to GflAx.