"For me, it's standing up for myself," said 26-year-old Malori Wampler.
Wampler's attorney, Kimberly Jeselskis, said the pictures were taken at a party thrown by Playboy, and that her client never posed for the magazine, but took pictures with guests at a golf outing.
"Some of them made it on the website," Jeselskis said.
The lawsuit claims the team discriminated against Wampler because she is a woman and Indonesian. The filing also points to Colts players who have broken the law but not received the same degree of punishment from the team.
"It kind of represents the double standard in the workplace," Jeselskis said.
Jeselskis also said a white cheerleader who was on the squad last season posed in a provocative photo while she was on the team. She said the white cheerleader wasn't disciplined and made the 2011 squad.
"It looks as if the Caucasian cheerleader was treated better. The rule was not applied the same way," Jeselskis told the station.
Jeselskis says the nature of the firing is ironic, considering what Wampler wore in front of thousands of football fans.
"They're not out there in jumpsuits," said Jeselskis, adding that "Miss Wampler was fired for body paint that was, in our opinion, not as revealing as the swimsuit she posed for in the (Colts' annual) swimsuit calendar."
Jeselskis said Wampler is entitled to get back her job, lost wages and damages.
For Wampler, the dismissal stings as a longtime fan of the team.
"Especially being a true Colts fan all my life and then getting to cheer for them, it's amazing," Wampler said. "Now it's just a little hard, because you feel like they don't quite respect you the way that they should."
Dan Emerson, the Colts' general counsel, said Wampler's "claim or claims have no merit whatsoever ... It's a very sad situation that it's gone as far as it has."
The Associated Press contributed to this report.