This is set in the php.ini file. Look for the upload_max_filesize setting:
; Maximum allowed size for uploaded files.
upload_max_filesize = 5M
Your friends over here at WebAssist! These Dreamweaver extensions will assist you in building unlimited, custom websites.
These out-of-the-box solutions provide you proven, tested applications that can be up and running now. Build a store, a gallery, or a web-based email solution.