UI image appears after "picking up" item

So basically I need to make an image appear on the UI after the player has triggered a collider with another item. None of the scripts that I have found so far have been of any help. If anyone has an easy and clean script that I could use it would help me a lot.

Thanks in advance

Just so I understand you correctly. You have two non-ui 3D / 2D objects which have colliders and when they collide, you want a UI object to appear?

Would it not just be easy enough to keep a reference to the UI GameObject in one of the scripts (or a manager) and then just enable / disable the UI when OnCollision methods fire?