Image Upload doesn't work

HI EveryOne,
I have a form having Image file upload field along with some other fields.
My Actions
=> I altered form using form_alter and created a new fieldset. And wish to bring the image field to be in that fields set.
=> I restricted the numbers of uploads to only 1.
=> The image field is visible in the new fieldset but when I upload the image it doesn't and no image wrapper visible.

Code :
$form['product_info'] = array (
'#type' => 'fieldset',
'#title' => 'Product Details',
'#collapsible' => 1,
'#weight' => 0,
);
$image = $form['field_image_cache'];
unset($form['field_image_cache']);
$form['product_info']['field_image_cache'] = $image;

Please Help !