Hi there, I just tested the new Safari 15.1. Beta on macOS Big Sur. With this version all my backgrounds work again. So I think we “only” have to wait for Apple to fix their browsers.
I had the same problem: I created a personal php.ini, changed the 2M value, <?php phpinfo(); ?> in the root directory showed the new value, yet no change.
I found that the value had not changed inside /wp-admin. So to test do create the phpinfo.php INSIDE /wp-admin. In my case I just needed to copy the new php.ini to the wp-admin directory to solve the problem.
