Apple ID profile picture

Whenever I turn my MacBook Air on, my profile picture seems to be minimised and put into the Botton left corner. Sometimes it is black and sometimes it is grey. The small picture also isn't my Apple ID profile picture, it is just a random photo from my gallery. If I go onto settings and the App Store my profile picture seems to be fine but whenever I turn on my MacBook Air it seems to be different. Does anyone know how I can fix this?