BuddyPress.org

Have a look at https://codex.buddypress.org/how-to-guides/changing-internal-configuration-settings/ (“avatar specific settings”).

However, that’s a PHP memory limit which you might want to see if you can increase on your host. It currently appears to be 40Mb-ish? Try setting to at least 64Mb, as such (in wp-settings.php) by doing this:

define(‘WP_MEMORY_LIMIT’, ’64M’);