For Windows XP, there is a power tool that lets you rotate images by right-clicking. Now, there is this feature for Knoppix too. Simply run the following or put it in your knoppix.sh and then you can rotate images in Konqueror with a right-click.

Code:
#!/bin/bash

#################### OUTDATED, FOR NEW VERSION SEE BELOW #################### 

# rotate images by right-clicking in Konqueror
# by probono
# This script is published under the GPL

mkdir -p ~/.kde/share/apps/konqueror/servicemenus

cat >> ~/.kde/share/apps/konqueror/servicemenus/rotate_ccw.desktop <<EOF
[Desktop Entry]
ServiceTypes=image/png,image/jpeg,image/gif
Actions=rotate_ccw

[Desktop Action rotate_ccw]
Name=Rotate counter-clockwise
Icon=rotate_ccw
Exec=/bin/sh -c "for file in %U; do mogrify -rotate 270 $file; done"
EOF

cat >> ~/.kde/share/apps/konqueror/servicemenus/rotate_cw.desktop <<EOF
[Desktop Entry]
ServiceTypes=image/png,image/jpeg,image/gif
Actions=rotate_cw

[Desktop Action rotate_cw]
Name=Rotate clockwise
Icon=rotate_cw
Exec=/bin/sh -c "for file in %U; do mogrify -rotate 90 $file; done"
EOF