To unlock the "Casual Perfectionist" trophy in Pic-a-Pix Color, you must get a medal on all of the 10x10 grid puzzles (Puzzles 6-50). It doesn't have to be a gold one.
You'll only realistically mess up getting at least some sort of medal if you hit
at any time. This is the "Fix" option, prompting the game to automatically fix any errors that you have made and voiding all medals on completion. Otherwise unless you spend crazy amounts of time on each puzzle you'll at least earn some sort of medal if not a gold one.
You can skip the puzzling by following the solutions in the below Google Drive folder I'm putting together. This will eventually contain every puzzle solution. Get some sort of medal in puzzles 6-50 to unlock the trophy.
https://drive.google.com/open?id=1GouHjmn9DNF034KII1A96lGLKD...