Generally PHP has a 2 MB limit - which you can't override from within threads. If it's your server, you can edit the php.ini file for your PHP configuration and raise the limit. Otherwise on most servers, the default max built into php for file uploads will be 2MB.
Donate to UBBDev today to help aid in Operational, Server and Script Maintenance, and Development costs.
Please also see our parent organization VNC Web Services if you're in the need of a new UBB.threads Install or Upgrade, Site/Server Migrations, or Security and Coding Services.