Create custom image attribute in magento

First Create "size_image" attribute type media gallary and set below code

<?php if($_product->getSizeImage() && ($_product->getSizeImage() != 'no_selection')): ?>
        <div class="rightimage">
                <img src="<?php echo $this->helper('catalog/image')->init($_product, 'size_image');?>">
        </div>
<?php endif; ?>
                        
also set its placeholder in this skin directory : images/catalog/product/placeholder/size_image.jpg

Add “Back Order” field in “Quick simple product creation” in magento

$fieldset->addField(‘simple_inventory_backorders’, ‘select’, array(
‘label’ => Mage::helper(‘catalog’)->__(‘Backorders’),
‘name’ => ‘stock_data[backorders]’,
‘values’ => array(
array(‘value’=>0, ‘label’=> Mage::helper(‘catalog’)->__(‘No Backorders’)),
array(‘value’=>1, ‘label’=> Mage::helper(‘catalog’)->__(‘Allow Qty Below 0’)),
array(‘value’=>2, ‘label’=> Mage::helper(‘catalog’)->__(‘Allow Qty Below 0 and Notify Customer’))
)
));

In app/code/core/Mage/Adminhtml/Block/Catalog/Product/Edit/Tab/Super/Config/Simple.php