Pontifications

See How can I combine these commands to achieve circular crop in ImageMagick?
Gotta try this with my Berlin July 2019 photos and then make a collage of these circular crops!

Code

convert -size 200x200 xc:Black -fill White -draw 'circle 100 100 100 1' -alpha Copy mask.png

for f in $(ls *.jpg)
do
  convert $f -gravity Center mask.png -compose CopyOpacity -composite -trim ${f}_output.png
done