Tattoo Tryout

Before I get a tattoo, I would like to have the opportunity to see how the tattoo would look on me before I actually get inked up. I need an app where I can take my tattoo idea and a photo of the specific part of my body to see how the tattoo would look before I get it. Example: I want to get a tattoo of a tree on my forearm. I upload a pic of my forearm, and upload my tattoo idea and place the tattoo idea where I want it on my forearm to see how it looks before I go through with getting the actual tattoo.