I use Linux and GIMP i always use. I have often having to rescaling dozens of images from 8 Mpx to 1 Mpx for use online. With the GIMP i had to do it one at a time ( !) since it does not have the immediate possibility to use macros. I have resolved by writing the Bash shell scripts that there i enclose. Use the shell command "convert". Here's the script.
#!/bin/bash
#
#Scala.sh
#
#by KMZ 2012.-
#
fine () {
exit 0
}
if test -z "$1"
then
echo "use: scala.sh directory 400x300"
echo "to resize 400x300px all the images into directory"
fine
fi
q=$(ls -1 $1/*.* | wc -l)
echo "I'll do for $q files."
for file in $(ls -1 $1/*.*); do
echo $file
convert $file -resize $2 $file
done
echo "Done."
fine
Edited: English Language Only Please