Open Root Terminal (Applications -> System Tools -> Root Terminal).
sudo gedit /etc/php5/apache2/php.ini
and press enter key.
You will get gedit application with the php.in file.
Search for the words post_max_size & upload_max_filesize.
If you found the words you will see a = after the word post_max_size & upload_max_filesize.
Change the number as you want (Default will be 1M or 2M).
After editing save the file and restart Apache Web Server by opening Root Terminal and pasting this code
sudo /etc/init.d/apache2 reload
and press enter.
That’s it. Upload a file in PHP and see the magic !