I've been using epeg for an NAS device as it can make thumbnails
rather quick (faster than convert). Though it's result might not look
as sharp as the result from imagemagick, I think it can be used as an
intermediate format when converting large jpegs.
If you want to test out epeg, we are keeping a debian package at
http://update.excito.org/pool/main/e/epeg/
Following are testing output I've made on my desktop computer (images
are attached, original can be found on commons):
[0:0][azatoth@azabox img]$ time epeg Boucher\,\ Francois\ -\
Landscape\ Near\ Beauvais.jpg epeg_direct.jpg -w 800 -w 600 -m 800 -q
100
real 0m3.957s
user 0m3.460s
sys 0m0.076s
[0:0][azatoth@azabox img]$ time epeg Boucher\,\ Francois\ -\
Landscape\ Near\ Beauvais.jpg epeg_tmp.jpg -w 1600 -w 1200 -m 1600 -q
100
real 0m5.896s
user 0m5.120s
sys 0m0.088s
[0:0][azatoth@azabox img]$ time convert epeg_tmp.jpg -quality 80
-thumbnail 800x -depth 8 epeg_convert.jpg
real 0m0.942s
user 0m0.696s
sys 0m0.032s
[0:0][azatoth@azabox img]$ time convert Boucher\,\ Francois\ -\
Landscape\ Near\ Beauvais.jpg -quality 80 -thumbnail 800x -depth 8
convert_direct.jpg
real 0m12.007s
user 0m9.929s
sys 0m0.800s
[0:0][azatoth@azabox img]$ ll Boucher\,\ Francois\ -\ Landscape\ Near\
Beauvais.jpg
-rw-r--r-- 1 azatoth azatoth 104554102 8 aug 04.16 Boucher, Francois
- Landscape Near Beauvais.jpg
[0:0][azatoth@azabox img]$ identify Boucher\,\ Francois\ -\ Landscape\
Near\ Beauvais.jpg
Boucher, Francois - Landscape Near Beauvais.jpg JPEG 12384x10064
12384x10064+0+0 8-bit DirectClass 99.71mb
[0:0][azatoth@azabox img]$
--
/Carl Fürstenberg <azatoth(a)gmail.com>