My kids pretty much ignore the pictures for simple puzzles. This is what I remember. In all cases it was the first time they encountered the puzzles.
My older one could do 24 piece puzzle without the picture at 2.5 and 160 without the picture the month he turned 4.
My younger one is even better. He could do 50 piece puzzles at 23 months and 60-piece puzzle at 25 months, both without the pictures.
DS5 put together 600 piece puzzle without any help a few weeks ago. It was a major project for him and took him a few weeks to finish. He did use a picture for this one.
