BULK GENERATING OG IMAGES -- Zach Leatherman: https://www.zachleat.com/web/bulk-og/

ogprep.sh

# prepare images for og serving
echo "Uses imagemagick."

images="input/*.png"
watermark="watermark.png"
outputDir="output/"
bgColor="#00dc9e"

mkdir tmp/
mkdir $outputDir

convert "$watermark" -resize x60 -gravity center -background "transparent" "tmp/watermark.png"

for i in $images
do
	# resize image
	convert "$i" -resize x530 -background $bgColor -gravity center -extent 1200x630 "tmp/${i##*/}"
	# add watermark
	composite -gravity SouthEast -geometry +20+20 "tmp/watermark.png" "tmp/${i##*/}" "${outputDir}${i##*/}"
done

rm -rf tmp/