So I am making a game in Unity for a school project but I am still a beginner, and I am stuck at this.

I have 5 images from which I want 1 image to appear when the button in my game is clicked. So that the 1st image has a 50% chance of appearing after button clicked, 2nd image has 30% chance of appearing after clicked, 3rd image has 10% chance of appearing after button clicked, 4th image has 7% chance of appearing after button clicked and the 5th image has 3% chance of appearing after button clicked.
If you know how to make the images go into a score counting table, I will pay extra 5€.