To "sell" something can mean to speak convincingly. To sell a car can mean just to take money for it, but it can also means what a salesperson does. The salesperson makes a sales pitch, tells you why the car is good, tells you why the price is good. Well, it can also mean to "sell" an idea. "Don't just stand there when you sing, move around--your body language is what sells the song."
"You'll want to bury my denial in the last paragraph, and see if you can find a picture of me from back then" is saying two unrelated things that probably should be two separate sentences. The grammar is correct but it isn't good style. In a newspaper story, to "bury" something means to put it near the end, because many people will just glance at the beginning and won't read all the way to the end. Here, the person is saying that for some reason the denial needs to be in the story and can be left out, but he or she doesn't actually want people to notice it.
Without more context, I can't tell what they mean about the picture. If the story is being printed in 2014, and it is about something that happened, say, in 2001, "see if you can find a picture of me from back then" means "use an old picture of me as I looked in 2001."