Anyone know what this art is called?

So I already know that this type of image goes all the way back to Victorian times. It can be described as risque, and called an optical illusion. I've been looking, searching, to try and find out if it has an actual name for the style.

Anyone?

 

what you mean is probably "risqué".
no mark on the bottom ?

 

Risque, risqué, potato, potato . No, there's no mark on the bottom, not that it matters. This type of image has been on celluloid backed mirrors, trade cards, even found in old newspapers ads.