A federal judge Tuesday allowed the movie “Hangover Part II” to be released for the Memorial Day weekend, rejecting a request by a tattoo artist who says that the movie violates his copyright by using a face tattoo he made for Mike Tyson on a central character in the movie.

But even as Judge Catherine Perry of Federal District Court in St. Louis gave an important victory to Warner Brothers Entertainment, the studio that is releasing “Hangover Part II,” she made clear that her sympathies were on the side of the artist, S. Victor Whitmill.

She said that Whitmill had a “strong likelihood of prevailing on the merits for copyright infringement” and that most of the arguments put forward by Warner Bros. were “just silly.”

Shown on Tyson’s face, the tattoo has appeared in numerous movies, including the original “Hangover,” which made more than $250 million, and the documentary “Tyson.” But in the sequel to “Hangover” the tattoo was shown on the face of another character, Stu, played by Ed Helms.

With the tattoo’s use in the movie or promotional items like movie posters, iPhone apps or Big Gulp cups at 7-11, Whitmill had “lost control over the image he created,” Perry ruled.

By her own reasoning, the judge conceded, she should have enjoined the studio from releasing the film — a decision that could have cost the studio as much as $100 million. But ultimately she concluded that the harm to the “public interest” from stopping the release of the movie outweighed the harm to Whitmill.