Uploading Large Lmage

[eluser]Musaddiq Khan[/eluser]
Hi everybody,
I m using codeigniter upload library for uploading images. It's working fine.
But problem is that when I uploading larg file of size round about 4 MB.
It does not work.
I've set the configuration as shown below.

Code:

ini_set( 'memory_limit', '2000M' );
ini_set('upload_max_filesize', '2000M');  
ini_set('post_max_size', '2048M');  
ini_set('max_input_time', 3600);  
ini_set('max_execution_time', 3600);

$config['max_size'] = '1000000';
$config['max_width']  = '1024000';
$config['max_height']  = '768000';

but it don't work for me
...
Thanks

[eluser]InsiteFX[/eluser]
post_max_size - Sets max size of post data allowed. This setting also affects file upload. To upload large files, this value must be larger than upload_max_filesize.

Code:

ini_set( 'memory_limit', '256M' );
ini_set('upload_max_filesize', '12M');  
ini_set('post_max_size', '16M');