I live in Oregon and own a business. I was selling my "personal" car on Craigslist. Someone became interested but was unable to make full payment and mentioned making monthly payments while I keep the car in my garage. We made a contract, sealed and initialed with tape over it agreeing upon payments, which took place at my business. The contract was only between "My name" and "His name", nothing included my business name. If contract was breached within 30 days after late payment, I had the right to sell that car. He breached contract. He now put my business on ripoffreport.com including my business name saying I'm a scam artist and to not trust me with a long story attached. He included a picture of me I had on my personal Facebook account that I did not give him permission to.
Although I don't practice in Oregon and Oregon laws may differ, there are certain truths about Intellectual properties and defamation claims that hold true across state lines. When it comes to suing someone for slander, usually as long as the statement was a FALSE statement and it was communicated to a 3rd party and you suffered some harm, then you can definitely sue. Just remember there can be no TRUTH to the statement made in order to prevail.
As for the claim regarding use of your picture, based on the information you gave, the use of the picture doesn't really factor into the lawsuit. You might have a claim for misappropriation of property, but it's a stretch.