For resizing image using Qimage component in cakephp first we have to  download Qimage plugin  after downloading Qimage plugin we have to put it into  App/Controller/Component .

Then we have to do all this in our controller.

class UploadsController extends AppController {    

    public function add(){


    	 if ($this->request->is('post')) {
        	$this->Upload->create();


         

      if ($this->request->data['Upload']['photo']!='' && is_array($this->request->data['Upload']['photo'])) {
            $imgData = array();
            $imgData['file'] = $this->request->data['Upload']['photo'];
            $imgData['name']=$this->data['Upload']['photo']['name'];
            $imgData['path'] = WWW_ROOT . '' . '/images/'; // path where the image will we copied
            
            $user_image = $this->Qimage->copy($imgData); //Qimage copy function

            
              // Qimage resizing function,
            $this->Qimage->resize(array('height' => 80, 'width' => 80, 
                                 'file' => $imgData['path'].$user_image, 
                                 'output' => WWW_ROOT. '/images/thumbnail/'  // path where the image will we uploaded after resizing
                                     )
                                   );
        }
      else{
            $user_image = "";
      }
         

        

    }

In above code firstly we are copying our image with the help of $this->Qimage->copy(); function  in our webroot/images folder after copying we are resizing image with the help of $this->Qimage->resize(); function and then storing it in webroot/images/thumbnail folder.