To give your Gallery a Cover Photo that's different than what you've chosen for your Collection, you'll need to navigate to your Gallery Settings.
First, select the Collection you’re working on, and then click on 'Galleries & Apps' at the top.
Click 'Edit' and select the 'Cover' tab.
To change the Cover Photo, click on 'Change Cover Photo'. Choose the photo you would like it changed to by dragging it from your computer or browsing photos from your files, and click on 'Publish' or 'Update'.
✨ POOF ✨
Your Cover Photo will now be changed and visible in your Gallery! 🙌