It does not valid, i had already reload or restart my forum, and when i access "*/uploads/system/gravatar-default.png" i could see the image what i upload, but it didn't apply to a new user.
@julian a bug?
disable Convert profile image uploads to PNG
save and reload
Good work @julian!
In the ACP you can give the image a class. Use cover to have it fit the box. Or you can give anything you want and then customize in the theme CSS override.
Though, I checked now.
I can create 1 million files in a directory on my Ubuntu box with the ext4 file system.
So, it should work with the current configuration.
Pretty sure its the regex in composer-default plugin that's exploding on those chars.