Werner von Braun and Neil Armstrong met with each other several times over the course of their lifetimes. I am not yet certain if pictures were taken at any of these meetings, or where to find these photographs, but I do know that they met.
The first time the two met was in, I believe, 1962, when Neil Armstrong and eight other astronauts-in-training visited the Marshall Space Flight Center in Huntsville, Alabama. To the best of my knowledge, no photographic evidence of this meeting was likely taken, since Neil Armstrong had not yet been selected for the lunar mission, and the two likely only met for a short time. Most of Neil Armstrong's time would have been spent touring the facilities and examining the experimental aircraft/spacecraft at the facility, but not with the head scientist.
They may have met again before the lunar landing, but I was unable to find documentation of it, or, to be honest, a time when Neil Armstrong was free enough that the two of them could afford a visit. I have a hunch, however, that Wernher von Braun would have been interested enough to visit Neil Armstrong at some point to observe his training, though this would have been an informal visit and probably not photographed.
After the successful lunar landing mission, Neil Armstrong and Wernher von Braun apparently became friends, though their in-person meetings were infrequent.
The two met for a final time in 1976 when Wernher von Braun was dying of cancer in Alexandria Hospital. Neil Armstrong and Wernher von Braun had by this time become good friends, and as far as I can tell, Armstrong was the only one of von Braun's astronauts that visited him at this time.
Two sources I perused heavily to research this post were the book "First Man: The Life of Neil A. Armstrong" by James R. Hansen and "Doctor Space: The Life of Wernher von Braun" by Bob Ward.