As I was composing this post in my head I mostly made my decision, but what the hell, I'll run it by you all just to make sure I'm not being terribly rude.
I completed a graduate degree in 2004. One of my co-advisors for that degree is retiring this year. His current student contacted all of his past students via email, including me, asking for pictures or messages to be included in a printed and bound book for his retirement.
I did not keep in touch with this advisor after I gradated. It wasn't a close mentor/mentored relationship. It wasn't awful, it just wasn't anything. He was chair of the department while I was his student and I feel like I fell through the cracks. Of course a bad case of procrastination on my part didn't help much either.
I haven't responded to any of the student's messages yet and I'm leaning towards not responding. I might have pictures on an old hard drive somewhere but I can't remember and I haven't taken the time to dig it out.
Or I think I could send a message of "Best wishes on your next adventure!"
I'm feeling slightly guilty as the student sent a follow up message, which to me suggests people haven't responded.
What would you do?