I guess the creator of the balloon itself would own rights to it. I get confused, though, with what is regarded as public domain imagery and what isn't with stuff like this.
There are numerous options for unions too, including festering and non-festering belly as well as the greedy pig! http://www.bigskyballoons.com/ratpack.html]]>
However, how did I never notice the stomach of blistery infection?? Yikes! They could have photoshopped that part out!]]>