Hi there, @jkingma ...
It seems strange to me that your course image on your course "Settings" page would be tinted. The only place I know that a color overlay can be applied to images on course cards is on the Dashboard...not in a course "Settings" page. When you are on your Canvas Dashboard looking at your course cards (those are the ones with your course image displayed on them), click on the three-dot kebab icon near the upper right corner of the screen and make sure that "Color Overlay" is not selected. If it were selected, you would see color overlays on top of images on your course cards. However, even if your color overlay was turned on within the Dashboard...that shouldn't display the color overlay on your course "Settings" screen...at least that is how it is working in my own sandbox course.
Have you tried clearing your history/cache on your browser? Once you do this, close your browser completely, then re-start the browser, and see if anything has changed.
How do I clear my browser cache on a Mac?
Keep us posted on this...thanks!