One of the nice features of JPEG 2000 is that it's easy to downres an image -- just feed out fewer bytes.
Is there a similar way to scale the image, such that I could send a thumbnail using bytes in the full-size file, without resampling?
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I was just about to ask this question myself... – Ralphleon Apr 20 '10 at 17:54
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Can't you just reduce the quality of compression, e.g. `-quality 30`? The quality is in dB, the higher the better, with 0 lossless and +inf maximum. http://www.imagemagick.org/discourse-server/viewtopic.php?p=120931 – Nemo Feb 02 '16 at 11:26
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No, to resize you will still have to read the original size, resample to the new size, and then recompress.
You can write your file such that it has layers with powers-of-2 sizes, with a very small relative incremental increase in size, and extract those layers.
Mark Harrison
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