The Reference Library is a great way to compare color corrections from shot to shot, explore different treatments, or load reference stills to emulate a certain look.
To open the Reference Library, click on the down-pointing triangle located at the top of your preview window. When you first open the Reference Library, it will be empty. You can add reference images in two ways. First, you can click on the snapshot icon to capture your current preview image and its current look. Alternatively, you can click the "+" icon next to the snapshot icon and import images from local storage.
When you snapshot a reference image, its thumbnail moves into the leftmost position in your Reference Library. Whatever image is in this position becomes the reference still, which will appear on the left in your preview window. When you click another thumbnail in the Reference Library, that thumbnail will be outlined in yellow and its reference image displays on the right side of the preview window. Now, see that up-pointing yellow arrow just below the preview window? That’s your split-screen slider. Drag it from side to side to see how your two images compare.
If you ever want to delete a reference still or all Reference Library contents, right-click on a still in the Reference Library and choose Delete or Delete All. As you can see in the image below, this pop-up can appear some distance from the selected image. You may need to modify your layout to see it.