PHP:来自不同服务器的imagecreatefromstring

Ok I looked this up countless times. Many people said in order to use imagecreatefrompng('some sort of photobucket url or imgur.com'), you need to do this function:

$powered = imagecreatefromstring(file_get_contents('http://bowlinggreen.halfoffdeals.com/images/small_logos/bowlinggreen.png'));
$powered = imagepng($powered_by);

However, that doesn't help me. It gives me this error:

Warning: imagecreatefromstring() [function.imagecreatefromstring]: Empty string or invalid image in /usr/home/dev1/public_html/inline/iframe_special_gd.php on line 123

Warning: imagepng(): supplied argument is not a valid Image resource in /usr/home/dev1/public_html/inline/iframe_special_gd.php on line 124

Warning: imagecopymerge(): supplied argument is not a valid Image resource in /usr/home/dev1/public_html/inline/iframe_special_gd.php on line 129

I'm trying to get this URL as an image to merge it ontop of my current image :

$image = imagecreatefrompng('http://dev1.mogadore-deals2.com/images/gdprac/blank_template2.png');

imagecopymerge($powered, $image, 5, 10, 5, 10, 150, 148, 100);

    imagefttext($image, 8, 0, 163, 20, $color, '../images/gdprac/LUCIDASANSSTD-BOLD.OTF', 'Your Price:');
    imagefttext($image, 22, 0, 163, 48, $color, '../images/gdprac/LUCIDASANSSTD.OTF', '$'.$selling_price);
    imagefttext($image, 7, 0, 168, 70, $color, '../images/gdprac/LUCIDASANSSTD.OTF', 'Original Price');
    imagefttext($image, 11, 0, 182, 90, $color, '../images/gdprac/LUCIDASANSSTD.OTF', '$'.$certificate_value);
    imagefttext($image, 7, 0, 248, 70, $color, '../images/gdprac/LUCIDASANSSTD.OTF', 'Savings');
    imagefttext($image, 11, 0, 250, 90, $color, '../images/gdprac/LUCIDASANSSTD.OTF', '50%');
    imagefttext($image, 7, 0, 163, 153, $color, '../images/gdprac/LUCIDASANSSTD.OTF', 'Powered by:');

imagepng($image, '../images/gdprac/final_temp.png');