Replace colors in an image with random ones and assemble into a montage

randomize.sh

set -ex
ORIGINAL="fox.jpg"
OG_SHIRT="#224e2b"
OG_PANTS="#9f6e4e"

function rand {
  echo $(($1 + ($RANDOM % ($2 - $1))));
}

mkdir -p tiles
for i in {1..60}
do
  PANTS="hsb(`rand 0 360`, `rand 0 100`, `rand 50 256`)"
  SHIRT="hsb(`rand 0 360`, `rand 100 200`, `rand 50 256`)"
  convert $ORIGINAL \
    -fuzz 10% -fill "$SHIRT" -opaque $OG_SHIRT \
    -fuzz 5% -fill "$PANTS" -opaque $OG_PANTS \
    tiles/$i.jpg
done
montage -geometry +0+0 -tile 20x3 tiles/* montage.jpg