I wrote to Mr. Cranston via the play, "All the Way" on February 4, 2014. I sent a LOR, photo, and SASE. On March 24, 2014, I received a different signed photo, along with my original photo not signed. He was even kind enough to use a piece of cardboard and an extra stamp.
Though I think there is a pretty good chance that it is pre-signed, I am still very happy. He is a fantastic actor, having been part of some of my favorite shows ("The Office," "30 Rock," "King of Queens," "SNL," "Family Guy," etc.), and of course the excellent "Breaking Bad."
Photo:

"All the Way"
The Neil Simon Theatre
250 W 52nd St
New York, NY 10019
What do you guys think: authentic, pre-signed, pre-print, autopen? I'm happy either way. Thanks Mr. Cranston!