I thought the aim was to post only signs that we had actually seen ourselves. If it is free to post any funny sign found on the internet...oh boy, there are hundreds!
One that I saw, above the urinals in a public toilet read,
"Aim like a Jedi, not like a Storm Trooper".
I don't have a photo but about 25 yrs ago I saw a road sign outside a cattery. They were about to resurface the road, and the sign said
BEWARE CATS EYES REMOVED.
Some wag had made another sign of a cat with dark glasses and a long white cane. This one said
BEWARE BLIND CATS!
I nearly fell off my bike laughing.