Increase php.ini Upload Limit
From Lunarpages Web Hosting Wiki
How can you increase the PHP upload limit?
This can be done with the php.ini file. Here is how you do it:
Create a file under public_html and name it php.ini (if you do not have one yet.) Put the following in it:
upload_max_filesize = 5M
post_max_size = 5M
Replace the 5 with 20 or less. If you are letting other people upload, a size cap protects your storage space from abuse/overuse.
You will then need to add these lines in entirety to a .htaccess file: (Please replace "yourusername" with your cpanel user name an add to the end of the command line the folder(s) to the location of the php.ini file - Also there is a space between path and /home)
Now your PHP upload limit should be increased.