Env:Ubuntu 24.04.2 LTS + Linux code 6.11.0-17-generic
Unable to modify profile picture, open button displays gray.
Copy the png file format to /usr/share/pixmaps/faces directory, restart the computer, select the avatar file can not see the new copy of the file.
It’s a well-known bug that has been discussed a couple of times on the forum, @Tianyazi, and it’s still not fixed.
You just put your avatar in the wrong directory.
Follow @puffettacicciottella’s advice and you’ll be fine:
You didn’t follow the link I gave you in my first answer, did you ? 
Links in the note, thank you very much for your help, a temporary solution, put the head in the directory
/usr/share/pixmaps/budgie-faces,
can choose the head of the custom, I hope it helps others.
Install mugshot.
$ sudo apt install mugshot.
