As long as Disney has the trademarks, no one legally use Mickey's image without licensing it from Disney.
To use another example, The Wizard of Oz books are in the public domain but anything related to the 1939 film like the ruby slippers and Dorothy's dress can't be used because they're trademarked to Warner Bros through Turner Entertainment unless they license it. It'll be the same with Tom and Jerry and the Looney Tunes,