Sorry, but although I understand the concept of a watchdig this entry does not speak Heroes to me. For it to work, I'd want to see the dog *doing* something that suggested heroism. As this is, it kust looks like a snapshot of a dog lying down outside.
I understand that dogs have been heroic in the past, and some will be heroic in the future, but a shot like this, in a challenge of this type, does not say "heroes" to me.