access to a function in gdlib

[eluser]hht1230[/eluser]
The following works in a file outside CI:

$im = imagecreatefromjpeg('IMG_4025.jpg');
echo 'width=' . imagesx($im) . ' height=' . imagesy($im);

If I put it in a CI view file, I get

Message: imagecreatefromjpeg() [function.imagecreatefromjpeg]: URL file-access is disabled in the server configuration

What do I need to change / set to access imagecreatefromjpeg from inside CI?

thx,
Helen