iPhone/iPad:
Settings > [your name] > Edit in the Apple Account profile photo > Take Photo or Choose Photo > Choose.
Mac: Apple menu > System Preferences > Edit (in Apple Account profile photo next to name) > choose source of the photo > Save.
iCloud: iCloud's site > log in > Account Settings > Edit in Apple Account profile photo next to name > drag a photo into the box > Done.
"Can't change Apple ID account photo, keeps reverting to the old one again
I experienced this issue with my MacBook Pro. After wrestling with this for several days, I realized that the photo I was seeing was the one for my Mac User account, not the Apple ID account. When I updated the photo for the Mac User, the problem was resolved."
Can't change Apple ID account photo, keep… - Apple Community