Sexy photos are absolutely allowed, and they mean more to an inmate than most people realize. The guidelines are straightforward: lingerie shots, bikini photos, and tastefully suggestive poses are all fine. What crosses the line is exposed private parts or anything that would be classified as pornographic. Most facilities reject explicitly sexual material outright, and if it gets flagged in the mailroom, it never reaches him.
Strategic posing with hands placed carefully is generally acceptable as long as it stays on the tasteful side of the line. Think more along the lines of a magazine shoot than anything explicit. When in doubt, err toward leaving a little to the imagination. That approach tends to get through the mailroom and still accomplishes exactly what you are going for.
InmateAid's photo service is a reliable way to send pictures with your letter. The photos are printed in high quality and delivered in an envelope that protects them, and your home address stays off the outside of the envelope entirely.
On the perfume question, skip it. Spraying scent on a letter or envelope is one of the more reliable ways to get your mail returned or rejected. Mailroom staff flag anything that smells unusual because scented mail has been used to smuggle substances into facilities. The letter will not make it through, which defeats the whole purpose. Let the photos do the work.