It's a param in conf/_advanced.php, or at least I'm pretty sure it's in that file. For sure it's in that folder though, and there's only a few files to tinker with. Yeah. I'm pretty sure it's in _advance.php.

can't find it in there.

conf/_admin.php

/**
* by default, most servers limit the size of uploads to 2048 KB
* if you want to set it to a lower value, here it is (you cannot set a higher value)
*
* @global int $fileupload_maxk
*/
$fileupload_maxk = '50'; // in kilo bytes

/**
* you may not want all users to upload pictures/files, so you can set a minimum level for this
* @global int $fileupload_minlevel
*/
$fileupload_minlevel = 1;

thanks!