Thanks for the replies @Karl and @David_LaCivita! I’m aware of those functions, but I was specifically asking for a side by side situation. Side by side meaning, full picture on both sides. What @Karl shows in his screenshot is more of a split screen, which is not the most elegant solution for what I was talking about (aka copying a color grade from a reference image).
The current snapshot split screen works well for viewing before-after of the same image, but is not the best for working with reference images, in my opinion.