Imagemagick crop images to square

#!/bin/bash
#crops all images to a square
#set output size
size="300"

for i in ../imgs/*;
do
  #get longest side
  s="$(identify -format "%[fx:min(w,h)]x%[fx:min(w,h)]+0+0" $i)"
  convert $i -gravity center -crop $s -resize $size "$(basename $i)"
done