If you possess characteristics such as courage, chivalry, and determination, or are reckless or short-tempered at times, then you belong in Gryffindor House.
Harry, Ron, and Hermione are the most noteable members of Gryffindor House, although quite a few of the tattoos featured here actually feature Luna Lovegood.
Despite being sorted into Ravenclaw, Luna would wear a lion hat to support the Gryffindor team when they played Quidditch against Slytherin House. These tattoos are rather reminiscent of the neo trad or realism women tattoos where they have an animal head atop their own; a Luna/Gryffindor inspired piece could combine your love of that imagery and of Harry Potter.
Looking at the animal (lion), colours (scarlet and gold), and element (fire) associated with Gryffindor, you can provide your tattoo artist with some loose ideas and allow them the creative freedom to produce a Gryffindor tattoo just for you.