Mac login avatar broken (tiny avatar in the bottom left corner)

Shiky wrote:

I got my new MacBook Pro a few weeks ago and this problem persists starting from day one. In short, no matter how I change my avatar, the icon is always shrunk to the bottom left corner in the login page like this:

https://discussions.apple.com/content/attachment/5f8f6fc7-f9cf-407b-b9f2-75da33503272

However the avatar image displays well in the System Settings menu.

I've tried using different avatars, logging out of iCloud and then login again, and finally reset the PRAM, but none of these methods worked. Changing to another iCloud profile image did change this avatar in the login screen, but it was still very tiny and shrunk in the corner.

The only similar issue I can find online was dated back to 2011 in this thread (https://discussions.apple.com/thread/2721656), however there's no solution yet.

Have you tried other images to test...if all other image(s) load correctly it tells you your particular image file is corrupt.

Change a user's picture on Mac - Apple Support