The command line "sips" program can query or modify images. I particularly like that you can be very specific:
$ sips -g dpiHeight -g dpiWidth *jpg /Users/tony/103055x.jpg dpiHeight: 72.000 dpiWidth: 72.000 /Users/tony/apachecookbook.jpg dpiHeight: 72.000 dpiWidth: 72.000
The syntax for changing formats is a bit odd, but there's a lot of power behind it:
$ sips -s format jpeg picture.png --out picture.jpg /Users/tony/picture.png /Users/tony/picture.jpg $ ls -l picture* -rw-r--r-- 1 tony staff 240011 Sep 8 13:16 picture.jpg -rw-r--r-- 1 tony staff 23092 Aug 5 2004 picture.png $ file picture* picture.jpg: JPEG image data, JFIF standard 1.01 picture.png: PNG image data, 1085 x 1410, 2-bit colormap, non-interlaced
Interestingly, the man page for sips doesn't tell you about a lot of the syntax it recognizes. Probably most importantly it neglects to mention that "sips -h" and "sips -H" give much more information (and note that -h and -H give different help - you need both). You can flip images, rotate, change width and height, and much, much more.
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More Articles by Tony Lawrence © 2009-11-07 Tony Lawrence
Security is mostly a superstition. It does not exist in nature, nor do the children of men as a whole experience it. Avoiding danger is no safer in the long run than outright exposure. Life is either a daring adventure, or nothing. (Helen Keller)