this script will compress pdf, convert to picture, compress again and check the size. so you can use this script if your pdf file contain some secretly content to prevent other to stole it!

convert-raw-pdf-to-picture-pdf.sh

source_path='/path/to/booklet'
target_path='/path/to/result'

dpi=200
quality=25
max_size=1536 # in kb

pdf2pic() {
  dirname="${i%.*}"
  mkdir -p "$dirname"
  ghostscript -sDEVICE=pdfwrite -dCompatibilityLevel=1.4 -dPDFSETTINGS=/printer -dNOPAUSE -dQUIET -dBATCH -sOutputFile=output.pdf $1
  pdftoppm -png -r $2 output.pdf $dirname/pg
  convert -limit memory 1 -limit map 1 -compress jpeg -quality $3 "$dirname/*.png" "$target_path/$1"
  ghostscript -sDEVICE=pdfwrite -dCompatibilityLevel=1.4 -dPDFSETTINGS=/printer -dNOPAUSE -dQUIET -dBATCH -sOutputFile="$target_path/2$1" "$target_path/$1"
  mv "$target_path/2$1" "$target_path/$1"
  rm -rf $dirname
  wc -c "$target_path/$1" | awk '{print $1}'
}

mkdir -p $target_path

cd $source_path

for i in *.pdf; do
  echo $i
  result_size=$(pdf2pic $i $dpi $quality)
  if [[ $result_size -gt $(expr $max_size \* 1024) ]]; then
    pdf2pic $i $dpi $(expr $quality - 10)
  fi
done

rm output.pdf