Tyga and his lawyers are gunning for the people they say released pics of his exposed penis -- and the wild part is ... there's a Caitlyn Jenner connection to this whole story.

Tyga's lawyer, Lee Hutton, tells TMZ he believes the rapper is the victim of a conspiracy designed to "maliciously shame" him. While the photos are authentic -- you can see some of his tattoos -- Tyga's lawyer believes the person he sent them to betrayed him ... and used them to manufacture a fake story.

The blog that posted the pics is claiming Tyga sent them to a transgender model.

Hutton thinks that's also offensive because ... "The allegations are false and socially irresponsible during a time when many Americans are celebrating equality."

It's a clear reference to Caitlyn and the Supreme Court decision, and Tyga and Hutton's point is -- don't use transgender issues as a punchline.