This image comes from the 1930’s, and it shows that the curly-coated retriever was about the same size as a golden retriever.
Today, they have the highest maximum height at the withers and are normally quite a bit larger than goldens, flat-coats, and Labradors.
I’m not sure how one could compare heights on these dogs, as they are neither on the same plane for dorect comparison, nor is there any thing against which to measure each dog.
This illustration was one of a series done for National Geographic magazine. Miner was a competent illustrator, but nowhere near the caliber of Fuentes, Megargee or Lougheed (all of whom also did dog illustrations for NatGeo).
The ones that Binks painted were about the same size, if one uses the birds the dogs are retrieving as a guide.