File:Phalaenopsis 5kB.jpg

The image was produced by first scaling down the original picture in the GIMP and using ImageMagick convert to cut it into 8 pixel wide slices, which were each compressed at different quality levels using Perl and cjpeg and recombined with ImageMagick montage. The exact commands used were:

$ convert -crop 8x214 +adjoin Phalaenopsis_\(aka\).240x214.png Phalaenopsis_test_%02d.ppm
$ perl -e 'for $n (0..29) { system sprintf "cjpeg -optimize -sample 1x1 -dct float -quality %f Phalaenopsis_test_%02d.ppm
  >Phalaenopsis_test_%02d.jpg", 2+78*(1-$n/29)**2.3, $n, $n;}'
$ montage +frame +shadow +label -tile 30x1 -geometry 8x214+0+0 -quality 80 Phalaenopsis_test_??.jpg Phalaenopsis_JPEG.jpg

The expression 2+78*(1-$n/29)**2.3 produces a nonlinear quality gradient from 80% down to 2% quality. The exponent was chosen by trial and error to yield a nice looking image with a good balance of high and low quality areas.

I, the copyright holder of this work, hereby publish it under the following license:

This file is licensed under the Creative Commons Attribution-Share Alike 2.5 Generic license.

You are free:

• to share – to copy, distribute and transmit the work
• to remix – to adapt the work

Under the following conditions:

• attribution – You must give appropriate credit, provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use.
• share alike – If you remix, transform, or build upon the material, you must distribute your contributions under the same or compatible license as the original.

https://creativecommons.org/licenses/by-sa/2.5CC BY-SA 2.5 Creative Commons Attribution-Share Alike 2.5 truetrue