I use a pattern that I used to use many times, but when I click "Save" or "Save & Publish" images disappear from upload filed (like loosing linking between photo and page).

<?php

class AboutUsPage extends Page 
{    
    private static $allowed_children = false;
        
    public static $has_many = array(
        'AboutUsPhotos' => 'AboutUsPhoto'
    );
    
    public function getCMSFields() 
    {
        $fields = parent::getCMSFields();
             
        $fields->addFieldToTab('Root', new Tab('AboutUsPhotosTab', _t('AboutUsPage.AboutUsPhotosTab', 'Zdjęcia')));
        
        $fields->addFieldToTab('Root.AboutUsPhotosTab', $uploadFieldForPhotos = new UploadField("AboutUsPhotoPhotos", _t("AboutUsPage.AboutUsPhotosTab", "Zdjęcia")));   
        $uploadFieldForPhotos->setAllowedExtensions(array('jpg', 'jpeg', 'png', 'gif'));
        $uploadFieldForPhotos->setAllowedMaxFileNumber(3);        

        return $fields;
    }
}

class AboutUsPage_Controller extends Page_Controller 
{

}

class AboutUsPhoto extends Image
{
    public static $has_one = array(
            'AboutUsPage' => 'AboutUsPage'
    );
}

?>

Have you tried using a gridfield for the 'AboutUsPhotos'? eg

$fields->addFieldToTab('Root.AboutUsPhotosTab', new GridField('AboutUsPhotos', 'AboutUsPhoto', $this->AboutUsPhotos())); 

Here is the mistake

  new UploadField("AboutUsPhotoPhotos",