Batch resizing files and stripping meta data on the command line

the ‘convert’ tool

Man page:http://www.ma.utexas.edu/cgi-bin/man-cgi?convert+1
(Lots) of examples: www.imagemagick.org/Usage

Low level UNIX command line utility which is part of the ImageMagick graphics suite for messing around with images. It can do all kinds of fancy stuff , but the most useful one for Indymedia is probably batch resizing of images and reducing their disk size.

convert _image_filename_ -resize _dimension_ -quality _quality_% _output_filename_

e.g. to resize the file ‘46890.jpg’ so that its largest dimension is 650 px at 80% compression/quality and output to ‘46890_new.jpg’ invoke

convert 46890.jpg -resize 650x650 -quality 80% 46890_new.jpg

exiftool

Homepage: www.sno.phy.queensu.ca/~phil/exiftool

Command line utility written in Perl (so theoretically cross platform) which can be used to strip meta data from most AV files. To strip all meta-data from a file invoke

exiftool -all= _filename_

To strip all previous meta data and add the comment “Produced by Indymedia Birmingham collective” to ‘protest.avi’ invoke

exiftool -all= -comment='Produced by Indymedia Birmingham collective' protest.avi

A script for resizing files and stripping meta data in a folder

The following (quite hacky) bash script will find all image files with .png,.jpg,and .gif extensions and resize them to the second argument passed to the script and place them in a folder given by the first argument of the script.

#!/bin/bash
mkdir $1
find . -name \*jpg -printf %f\\n -or -name \*png -printf %f\\n -or -name \*gif -printf %f\\n >image_list
number=`wc -l <image_list|awk '{print $1}'`
for((i=1;i<=$number;i++)) do
image=`awk 'NR==j {print $1}' j=$i <image_list`
echo $image
convert $image -resize $2 -quality 80% $1/$image
exiftool -all= ${1}/$image
done
rm image_list