$setup = new Mage_Eav_Model_Entity_Setup(‘core_setup’);
$entityTypeId = $setup->getEntityTypeId(‘catalog_category’);
$attributeSetId = $setup->getDefaultAttributeSetId($entityTypeId);
$attributeGroupId = $setup->getDefaultAttributeGroupId($entityTypeId, $attributeSetId);

$setup->addAttribute(‘catalog_category’, ‘image1’, array(
‘type’ => ‘varchar’,
‘input’ => ‘image’,
‘backend’ => ‘catalog/category_attribute_backend_image’,
‘group’ => ‘General’,
‘label’ => ‘Banner Image’,
‘visible’ => 1,
‘required’ => 0,
‘user_defined’ => 1,
‘frontend_input’ =>”,
‘global’ => Mage_Catalog_Model_Resource_Eav_Attribute::SCOPE_GLOBAL,
‘visible_on_front’ => 1,
));

$setup->addAttributeToGroup(
$entityTypeId,
$attributeSetId,
$attributeGroupId,
‘image1’,
‘999’ //sort_order
);