----------------------------------- Single Cmd Parallel  ------------------------------
--------------------------------- 360 sec for 750 photos ----------------------------
#!/bin/bash
start=`date +%s`

mkdir cropped

parallel --eta convert {} -resize 1920x1440 -crop 1920x1080+0+$1 cropped/{} ::: *.JPG


end=`date +%s`

runtime=$((end-start))
echo "Runtime is $runtime"

----------------------------------- For-Loop Parallel  ------------------------------
--------------------------------- 370 sec for 750 photos ----------------------------
#!/bin/bash
start=`date +%s`

mkdir cropped

for f in *.JPG

do
    echo convert \"$f\" -resize 1920x1440 -crop 1920x1080+0+$1 cropped/\"$f\"
done    | parallel

end=`date +%s`

runtime=$((end-start))
echo "Runtime is $runtime"

------------------------------- 1 Convert cmd. No Parallel ------------------------------
--------------------------------- 410 sec for 750 photos --------------------------------
#!/bin/bash
start=`date +%s`

mkdir cropped

for f in *.JPG

do
    convert $f -resize 1920x1440 -crop 1920x1080+0+$1 cropped/$f
done

runtime=$((end-start))
echo "Runtime is $runtime"

------------------------------- 2 convert cmd. (Original Code) ------------------------------
----------------------------------- 545 sec for 750 photos ----------------------------------
#!/bin/bash
start=`date +%s`

mkdir cropped

for f in *.JPG

do
    convert $f -resize 1920x1440 -set filename:name '%t' cropped/'%[filename:name].JPG'
        convert cropped/$f -crop 1920x1080+0+$1 -set filename:name '%t' cropped/'%[filename:name].JPG'
done

end=`date +%s`

runtime=$((end-start))
echo "Runtime is $runtime"