PNG=$3
SHADOW=$(($SIZE / 16))
-IMAGE=$(($SIZE - $SHADOW))
-OPACITY=80
-BLUR=$(($SHADOW / 4))
-SHIFT=$(($SHADOW - $BLUR))
+OPACITY=60
+BLUR=$(($SHADOW / 2))
+
+if [ $BLUR = 0 ]; then
+ BLUR=1
+fi
+
+SHIFT=$(($SHADOW * 3 / 4))
+
+IMAGE=$(($SIZE - $SHIFT - $BLUR))
TMP=image-$$.png
convert $TMP \
\( +clone -background black -shadow ${OPACITY}x${BLUR}+${SHIFT}+${SHIFT} \) \
+swap -background none -layers merge -crop ${SIZE}x${SIZE}+0+0 +repage $PNG
-