We all had to start somewhere :)....
If this is your Background:
$fields->addFieldToTab('Root.Content.Main', new ImageField('Background'));
You dont't need my Image field....
It should be there in the cms, if you've added this to Page.php
public function getCMSFields(){
$fields = parent::getCMSFields();
// add the upload control for the background image to the cms
$fields->addFieldToTab('Root.Content.Main', new ImageField('Background'));
return $fields;
}
You can give it a new tab by changing Root.Content.Main to Root.Content.Background