That picture has become some sort of meme of itself (I've heard it referred as "you can see penguins through ECB") because it's so damn popular.
However ECB is a lot worse than "you can see data patterns"--with a chosen plaintext attack (very common scenario in networking and storage applications) any dumbass can decrypt it trivially.
Parent said "decrypt", not "get the decryption key", and parent is correct. The attack looks kind of similar to a "padding oracle attack", where you work one byte at a time using a block boundary.
