This quick script that generates an xml which can be consumed by the backgrounds config. This script was created by ozhoo in ubuntuforums http://ubuntuforums.org/showthread.php?t=1344787.
First you need to open wallpaper.sh file
gksudo gedit /usr/bin/wallpaper.sh
Copy and paste the following script
#!/bin/bash
#
# usage:./wallpaper.sh background_dir_1 background_dir_2 background_dir_3
#
# description: simply generate a backgrounds xml that can be consumed by gnome’s background configuration
#
# author: ubuntuforums.org username ‘ozhoo’
#
# note: only looks for .JPG and .jpg files
# output file
FILENAME=backgrounds.xml
# start time
YEAR=2009
MONTH=08
DAY=01
HOUR=00
MINUTE=00
SECOND=00
# time to show background (seconds)
WALLDURATION=900.0
# transition time (seconds)
TRANSDURATION=5.0
# script specifics
DIRS=$*
T1=”echo -e \t”
T2=”echo -e \t\t”
echo “” > “$FILENAME”
${T1}”” >> “$FILENAME”
${T2}”${YEAR}” >> “$FILENAME”
${T2}”${MONTH}” >> “$FILENAME”
${T2}”${DAY}” >> “$FILENAME”
${T2}”${HOUR}” >> “$FILENAME”
${T2}”${MINUTE}” >> “$FILENAME”
${T2}”${SECOND}” >> “$FILENAME”
${T1}”” >> “$FILENAME”
get_first()
{
for d in $DIRS; do
find “$d”|grep -i .jpg|while read j; do
echo “$j”
break
done
break
done
}
FIRST=”$(get_first)”
${T1}”” >> “$FILENAME”
${T2}”${WALLDURATION}” >> “$FILENAME”
${T2}”${FIRST}” >> “$FILENAME”
${T1}”” >> “$FILENAME”
${T1}”
” >> “$FILENAME”
${T2}”${TRANSDURATION}” >> “$FILENAME”
${T2}”${FIRST}” >> “$FILENAME”
for d in $DIRS; do
find “$d”|grep -i .jpg|while read j; do
if [ "$j" == "$FIRST" ]; then
continue
else
${T2}”${j}” >> “$FILENAME”
${T1}”” >> “$FILENAME”
${T1}”” >> “$FILENAME”
${T2}”${WALLDURATION}” >> “$FILENAME”
${T2}”${j}” >> “$FILENAME”
${T1}”” >> “$FILENAME”
${T1}”
” >> “$FILENAME”
${T2}”${TRANSDURATION}” >> “$FILENAME”
${T2}”${j}” >> “$FILENAME”
fi
done
done
${T2}”${FIRST}” >> “$FILENAME”
${T1}”” >> “$FILENAME”
echo “” >> “$FILENAME”
Save and exit the file.
Now you need to give excute permissions for your script
chmod +x wallpaper.sh
Using this script
/usr/bin/wallpaper.sh background_dir_1 background_dir_2 background_dir_3
Note:- This script only looks for .JPG and .jpg files
More: continued here