for i in *.JPG; do
	odkud="$i"
	# fotka.JPG --> fotka-thumbnail.JPG
	kam="`echo "$i" | sed 's/\.JPG$/-thumbnail.JPG/'`"
	kam="${i%.JPG}-thumbnail.JPG"
	echo convert \""$odkud"\" --thumbnail 600x800 \""$kam"\"
done