Okay. I changed yours to the cat you see displayed. I'm not sure why you are having trouble...perhaps the picture you are trying to use is too large??? Or wait...is there another profile picture you are trying to change? I thought you meant the avatar that is displayed in posts but ?????
OKAY...I went and checked again....was it the yellow flower you were trying to change??? If so I changed that to the cat too....so the function is working...must be picture size perhaps?
Let me know. Sorry for changing your avatar and profile picture...hopefully you can get them back to something you like....if not...let me know.