Set the Maximum Upload Size for the Whole Network
Overrides the network's "Max upload file size" setting from code, so every site gets the same per-file limit regardless of what is stored in the database.
Snippet Library
Multisite snippets for WordPress
Snippets for WordPress Multisite networks: network-wide settings, new site defaults, super admin tools and cross-site tweaks. For network administrators who manage many sites from one install.