What county should I file a small claims case against a wedding photographer? County of contract signing, county she lives in, or county of the event?

Start with the contract itself – does it have a paragraph, likely toward the end that specifies where a lawsuit is to be filed?  If not, you look to the Florida statutes.  Was the photographer set up as a business entity?  If so, according to Florida Statutes 47.051, you may file the action “only in the county where such corporation has, or usually keeps, an office for transaction of its customary business, where the cause of action accrued, or where the property in litigation is located.”  From your stated facts, if we’re dealing with a corporate entity, you can bring it where there’s an office or where the wedding was held.  If the photographer is just an individual, then according to Florida Statutes 47.011 you can bring the action either in the county where she lives or where the cause of action arose (i.e. where the wedding was held).  Since you’re bringing the suit, you can choose.  Frankly, absent a contract provision dictating the venue, I’d bring the action in the county in which she resides.  Saves any chance she’ll try to argue wrong venue.