The answer depends on whether you are still on good terms with the gentleman that has the pictures. If you deleted them, how are you sure that he still has them? Is it possible he is lying to you?
You may have a number of criminal (speaking to a prosecutor) or civil (speaking to an attorney) remedies in Illinois depending on the facts of who took the pictures and under what circumstances they were taken. If you choose to act by speaking with the police or with an attorney the ramifications for the person who allegedly has possession of the photographs could be severe. I would recommend seeing what becomes of the situation first. Then you potentially may have legal options.
NOTE: This answer is not intended to be legal advice and should not be construed in that way. This answer does not create an attorney-client relationship and no such relationship may be created absent a signed retainer agreement. The author is licensed in Illinois only, and his answer is for educational purposes alone.