install :
sudo apt-get install imagemagick imagemagick-doc
example:
convert your_image.jpg your_image.pdf
mass conversion script:
# fulpath="/home/DJon/temp/file.tar.gz"
# dir="${fullpath%/*}"
# fname=${fullpath##*/}
# ext=${fullpath##*.}
file=`ls $1*.jpg`
#echo $flie
mkdir "$1ok"
for i in $file
do
fname=${i##*/}
#echo $fname
convert $i $1'ok/'$fname'.pdf'
done