There is very little information about animator Ken O'Brien online or in books. This is a screen grab from a short 1986 interview, which was posted on youtube by Jerry Beck. Here is the link:
What strikes me is that Ken in his demeanor and speech reminds me so much of Marc Davis.
Kind of serious, confident, with the occasional chuckle during his answers.
He mentions working with Fred Moore (among others), and I can clearly see that influence in terms of clarity and fluidity applied to key poses for this scene depicting Jim Dear from Lady and the Tramp.
At the end of the film Jim Dear takes a photograph of the new dog family. The old fashioned flash light explodes, resulting in smoke filling the room. Here he makes a run for the window, before opening it in order to clear the air.
O'Brien is in full control of animating this realistic design convincingly. The overall body rhythm reads simply and clearly. There was live action reference involved, but O'Brien always altered his animation drawings to get more dynamic results.
A final frame with effects from the scene.