numbered_images.sh

#!/bin/bash
#<nellyk89@gmail.com>
# http://dummyimage.com/600x400/000/fff&text=100000

BASE_URL="http://dummyimage.com/"
DEFAULT_SIZE="600X400"
DEFAULT_BG_COLOR="000"
DEFAULT_COLOR="fff"
START=1001
END=4000
SUFFIX=".png"

for ((i=START; i<=END; i++ ));
do
	echo "$BASE_URL$DEFAULT_SIZE/$DEFAULT_BG_COLOR/$DEFAULT_COLOR&text=$i"
	wget "$BASE_URL$DEFAULT_SIZE/$DEFAULT_BG_COLOR/$DEFAULT_COLOR&text=$i" -O "$i$SUFFIX" 
done