PHP复制图像，损坏图像

I have this command:

copy($value['formats']['format'], 'bookData/cover/'.$picturename);

When I open the image from $value['formats']['format'] it is no problem. When I open the image from bookData/cover, the file must be corrupt. I can't open it with Windows image viewer and I can't open it with Adobe Photoshop.

I have already tried this:

$content = file_get_contents($value['formats']['format'));
$fp = fopen('bookData/cover/'.$picturename, "w");
fwrite($fp, $content);
fclose($fp);

The same result. The server is an Apache with PHP7 on Ubuntu 16.04.