Can i not select a cover when i upload multiple images?

Hi, I'm kinda new to TikTok... When i upload a video i can select a frame from it and this will be my cover/wallpaper which you can see on my profile.. but when i upload multiple photos i can not select anything as cover, it just selects automatically the first photo..

So i uploaded 10 pictures where i was working on my car, it's like a slideshow. Before, then some repairing pictures, then after, and at the end me with the car.. How can i select a photo as my cover which is at the end? So just not the first one? Can i not select that or am i just blind?

Thanks