Prepares a #type 'file' render element for theme_input().
For assistance with handling the uploaded file correctly, see the API provided by file.inc.
array $element: An associative array containing the properties of the element. Properties used: #title, #name, #size, #description, #required, #attributes.
array The $element with prepared variables ready for theme_input().
function form_pre_render_file($element) {
$element['#attributes']['type'] = 'file';
element_set_attributes($element, array(
'id',
'name',
'size',
));
_form_set_attributes($element, array(
'form-file',
));
return $element;
}