Remove product image magento

$_product = Mage::getModel('catalog/product')->setStoreId($storeId)->load(2);
$removes[0] = a/b/aaa.png;
$removes[1] = a/c/bbb.png;
if(count($remove)>0){
 $attributes = $_product->getTypeInstance ()->getSetAttributes ();
 $gallery = $attributes ['media_gallery'];
$galleryData = $_product->getMediaGallery();
foreach($removes as $remove) {
foreach($galleryData['images'] as $image) {
if($remove==$image['file']){
$gallery->getBackend ()->removeImage( $_product, $image ['file'] );
}
}
}
$_product->save ();
}

multi select in custom module magento

$tool_cat_Arr = array(array('value' => '1', 'label' => 'Shirt'), array('value' => '2', 'label' => 'Tshirt'), array('value' => '3', 'label' => 'Custom'));


$fieldset->addField("tool_cat", "multiselect", array(
"label" => Mage::helper("storeinfo")->__("Tool Category"),
"name" => "tool_cat",
"values" => $tool_cat_Arr

));

filter in custom module magento

$stored = 25;

$storeinfo = Mage::getModel("storeinfo/storeinfo")->getCollection()->addFilter('storeowner_id',$stored)->load();

$storeinfoid = $storeinfo->getAllIds();

$Storeinfomodel = Mage::getModel("storeinfo/storeinfo")->load($storeinfoid[0]);