Prepare 360 photo for Facebook with max resolution

360-photo-facebook.sh

#!/bin/sh

# Resizes any equirectangular image down to the max resolution and file size
# that Facebook will allow and adds 360 metadata. Saves copy with _fb appended
# to file name.
#
# Usage:
# ./360-photo-facebook.sh equirectangular_360_image.jpg

# Max settings, working June 2023
max_width=16430
max_filesize_kb=16000

file=$1
filename="${file%%.*}"
ext="${file##*.}"
new_file="${filename}_fb.$ext"

echo "Resizing uniformally to max width $max_width pixels..."
convert "$file" -resize "$max_width"x "$new_file"
echo "Reducing max file size to ${max_filesize_kb}kb..."
convert "$new_file" -strip -define jpeg:extent="$max_filesize_kb"kb "$new_file"
echo "Adding equirectangular metadata..."
exiftool -overwrite_original -quiet -all= -ProjectionType="equirectangular" "$new_file"

echo "\nSaved $new_file!\n"