I would suggest you look at your PHP settings in admin. You can place whatever you want in Photopost but at no time are we going to override your server defaults we are a PHP program and as such limited by your servers PHP settings. Now as a default PHP is limited to 2mb uploads and if you want that higher you need to alter your servers PHP settings by editing the php.ini file. I can not say whether you have access to do that or not. If you have a VDS or DEDICATED server you should otherwise you need to ask your host about server restrictions.