Which artist drew two dogs in "Making Friends"?

Here are some clues:

1. The artist's works were featured on many covers of the Saturday Evening Post.

2. This one was published on September 28, 1929.

3. The collie with the “R”on the collar was the artist’s dog!

Answer: Norman Rockwell

Image: https://www.saturdayeveningpost.com/2018/02/dog-covers/