cURL Download of image isn't an image

Question

I'm downloading an image via curl from filepicker.io. Here's the downloading code:

if ($_GET['download']== 'true'){
          $downloadarray = array();
          while($row = mysql_fetch_array($res)){
            $url= $row['loc'];
            $path = 'tmp/';
            $path .= rand(100,999);
            $path .= $row['name'];
            $fp = fopen($path, 'w');
            $ch = curl_init($url);
            curl_setopt($ch, CURLOPT_FILE, $fp);     
            $data = curl_exec($ch);     
            curl_close($ch);
            fclose($fp);
            echo print_r($data);
            $downloadarray[] =  array($path, $row['name']);
          }


         $zipname = rand(0,9999) . 'download.zip';
          $zip = new ZipArchive;
          $zip->open($zipname, ZipArchive::CREATE);
          foreach ($downloadarray as $file) {
            $zip->addFile($file['0'], $file['1']);

          }
          $zip->close();
          header('Content-Type: application/zip');
          header('Content-disposition: attachment; filename=' . $zipname);
          header('Content-Length: ' . filesize($zipname));
          readfile($zipname);
          unlink($zipname);

        }

For some reason the downloaded file is an image, for example 'palm-tree.jpeg' but it isn't actually being stored as an image. There is no header information being added in the image file. When I open the image with Get Info on my mac a preview correctly renders but the file type is listed as Document. Am I doing something wrong?

EDIT: Now added full code including zipping

Answer 1

Remove:

fwrite($fp, $data);

When you use CURLOPT_FILE, cURL writes the results to the file, you don't need to do it yourself. $data contains true, and you're appending that to the file (actually you're appending 1 to the file, since you're converting true to a string when you write it).