How can I change image when click Icon?

Hello! I'm doing a dress up game for mobile and I've been struggling with the drag & drop system (items are too tiny for the screen) so I wanted to change for another type of dressup. The idea is that when I click the icon, the image of a clothing item appears bigger on the doll... But I can't figure how to do it! Can you guys help me with the codes? Also, how can I tell the game that a hair piece should stay in a certain place, for example? Do I code each image to appear in their specific canvas' map numbers? Thanks in advance!