I updated Mastodon a while back but I'm running it on an old Linux and the version of the graphics processor ImageMagik was too old, so I installed it from source to get it working.
But it wasn't.
It also needs libraries for PNG and JPEG to be installed to work.
I need to migrate it to a new Linux but also have a life
But if you were wondering that's why my profile picture wasn't working for a while.