Dan, could be you changed the image on your Profile page, but not your actual user avatar.
Go to your profile page Settings and check the avatar image that shows when you go to your "Account" TAB in your settings. Then once that's changed too, SAVE your settings and also clear your browser cache to see the new results.
Every member has both an Account picture and a Profile picture. Oe shows up only on your profile page, and the other shows up next to every post you make. When in your Settings, be sure to go to both TABS and upload your chosen avatar picture: your Account TAB, and your Profile TAB. Also remember to SAVE your changes at the bottom of each page before leaving the page, after uploading your new picture.
Those irritated by grain of sand best avoid beach.
-Strumelia proverb c.1990
updated by @strumelia: 09/12/19 11:15:23AM