We are able to replace the thumbnail that displays when you go into your library. We can add our own custom thumbnails. Be careful when choosing the size of thumbnail because if the image you choose is not the right ratio, the thumbnail will become pixelated.
To change your thumbnail, first go to your Library of Studio Recordings. From there click on the 3 dots next to your desired recording. Click the Replace Thumbnail option. Click and choose the file from your computer. Click Open
You should now be able to view your new thumbnail for your recording.