It is well known among cryptographers that ECB mode is insecure. The most famous demonstration of this is the ECB penguin. This is a simple script to produce your own ECB art using a .ppm image and a key of your choosing. Note: it only works well with images with repeating patterns such as simple digital images without a rich colour palette.
./encrypt.sh Tux.ppm my_secret_key
open ecb_encrypted_art_Tux.ppm