Magento : 调用文件上传 upload file frontend

bool mkdir ( string $pathname [, int $mode = 0777 [, bool $recursive = false [, resource $context ]]] )

$pathname should be the server path to the file and not a url

Try

$path = Mage::getBaseDir('media') . DS;

You should try using Varien_File_Uploader

include_once Mage::getBaseDir() . '/lib/Varien/File/Uploader.php';

/* Starting upload */
$uploader = new Varien_File_Uploader('filename');

// Any extention would work
$uploader->setAllowedExtensions(array('jpg', 'jpeg', 'gif', 'png'));
$uploader->setAllowRenameFiles(false);

// Set the file upload mode 
// false -> get the file directly in the specified folder
// true -> get the file in the product like folders 
//  (file.jpg will go in something like /media/f/i/file.jpg)
$uploader->setFilesDispersion(false);

// We set media as the upload dir
$path = Mage::getBaseDir('media') . DS;
$uploader->save($path, $_FILES['filename']['name']);

参考：http://magento.stackexchange.com/a/40744

如果想要裁图的话，可以参考下面代码：

include_once Mage::getBaseDir() . '/lib/Varien/File/Uploader.php';

$file                 = new Varien_Io_File();			
$imageDir       = Mage::getBaseDir('media') . DS .  'mbimages';
$thumbimageyDir = Mage::getBaseDir('media').DS.'mbimages'.DS.'thumbs';

if(!is_dir($imageDir)) $imageDirResult            = $file->mkdir($imageDir, 0777);         
if(!is_dir($thumbimageyDir)) $thumbimageDirResult = $file->mkdir($thumbimageyDir, 0777);     

//echo '<pre>'; print_r($_FILES); echo '==>'.$filename; echo '</pre>'; die;

if(isset($_FILES[$filename]['name']) && $_FILES[$filename]['name'] != '') 
{
	//echo '==>'.$_FILES[$filename]['name'];
	
	try {	
		/* Starting upload */	
		$uploader = new Varien_File_Uploader($filename);
	
		// Any extention would work
		$uploader->setAllowedExtensions(array('jpg','jpeg','gif','png'));
		$uploader->setAllowRenameFiles(true);
	
		// Set the file upload mode 
		// false -> get the file directly in the specified folder
		// true -> get the file in the product like folders 
		//	(file.jpg will go in something like /media/f/i/file.jpg)
		$uploader->setFilesDispersion(true);
			
		// We set media as the upload dir
		//$path = Mage::getBaseDir('media') . DS ;
		$path = $imageDir . DS ;
		$result = $uploader->save($path, $_FILES[$filename]['name']);
		$file = str_replace(DS, '/', $result['file']);
		###############################################################################
		// actual path of image
		$imageUrl = Mage::getBaseDir('media').DS."mbimages".$file;
		 
		// path of the resized image to be saved
		// here, the resized image is saved in media/resized folder
		$imageResized = Mage::getBaseDir('media').DS."mbimages".DS."thumbs".DS."mbimages".$file;					
		 
		// resize image only if the image file exists and the resized image file doesn't exist
		// the image is resized proportionally with the width/height 135px
		if (!file_exists($imageResized)&&file_exists($imageUrl)) :
			$imageObj = new Varien_Image($imageUrl);
			$imageObj->constrainOnly(TRUE);
			$imageObj->keepAspectRatio(FALSE);
			$imageObj->keepFrame(FALSE);
			$imageObj->quality(100);
			$imageObj->resize(80, 50);
			$imageObj->save($imageResized);
		endif;				
	
		$data[$filename] = 'mbimages'.$file;
	} catch (Exception $e) {
		$data[$filename] = 'mbimages'.'/'.$_FILES[$filename]['name'];
	}
}

更多图片处理方法请参考：magento图片处理 Customize Magento’s Image Resize Functionality

本文：Magento : 调用文件上传 upload file frontend