getimagesize（）不返回图像值

I am trying to use getimagesize function. I am using Dropzone.js for image upload and I am using codeigniter.

The upload function:

public function upload() //upload multiple images-dropzone

{ 
      if (!empty($_FILES)) {
        $tempFile = $_FILES['file']['tmp_name'];

    $fileName = str_replace(' ', '_', $_FILES["file"]["name"]);
    $file_name = substr(uniqid(rand()),0,10000).'_'.$fileName ;
        $targetPath = './uploads/';
        $targetFile = $targetPath . $file_name ;
        move_uploaded_file($tempFile, $targetFile);



    $this->thumb($targetFile,$targetPath,$file_name,$tempFile);     

}}

My thumb function:

function thumb($targetFile,$targetPath,$file_name,$tempFile)
{
    require_once('php_image_magician.php');

    $magicianObj = new imageLib($targetFile);

    list($width, $height, $type, $attr) = getimagesize($tempFile);  

    if($width = $height)
    {
    $magicianObj->resizeImage(150,150);
    }
    else if($width > $height)
    {
    $magicianObj->resizeImage(150,40);  
    }
    else
    {
    $magicianObj->resizeImage(40,150);  
    }


    // saving file to thumb directory
    $magicianObj->saveImage($targetPath . 'thumb/' . $file_name, 100);
}

In this condition I'm trying to compare the height and width but it's not working properly. It always takes the first condition.

You have used move_uploaded_file, so $tempFile will not be found after that cause it has been moved already, use copy() function rather.