Ah, here is a little snag, the button that says Change Thumbnail just sends one over to their profile album and then one can either slide around the photos to place one at the beginning of the album or they can upload a new one. So the button is sort of misleading because it doesn't really change the Profile Thumbnail. I never liked that and so always used the avatar module which stores the images separately. One can upload photos as an avatar or any image; such as on my profile here. The button technically should be "Go To Profile Album" because that is what it does; or I assume if you have set the thumb to be the avatar it takes you to the avatar section so "Go To Avatars." I will be removing that button anyway as well as the change cover button because I don't think they should be in the way when I view my own profile.
The other thing is why have the Profile Thumb twice; unless you remove the profile images block from the page. The Profile Thumb really does need to be separate; I achieve that by using the avatar module.
Basically most of this is nitpicking but if a user clicks on "Change Thumbnail" then that is what it should do. And having the images at the end will not change the thumbnail if they upload a new one. I guess we could put some directions on that page since it is obviously not intuitive. Then again, if the avatar module is used instead, that wouldn't work as profile images are not profile thumbs; avatars are. This is one area where Boonex screwed up on. Although for now I wouldn't waste time on it.