How do I within my UI make an image’s size match another image’s size on screen, from code while the game is running?
How would I go about this?
An Image component expands to fill up the object it is attached to, so you just need to make the objects be the same size.
The main variable for that is RectTransform.sizeDelta, but the anchors and scaling values will also affect the result. You might find it more convenient to call SetSizeWithCurrentAnchors depending on your circumstances.