add_action( 'user_edit_form_tag','make_uploadable_form');

function make_uploadable_form() {
	echo ' enctype="multipart/form-data"';
}

add_action( 'show_user_profile', 'UploadField' );
add_action( 'edit_user_profile', 'UploadField' );

function UploadField( $user ) {
	if ( ! current_user_can( 'edit_user' ) )
		return false;

	$pid = get_user_meta( $user->ID, 'profile_photo', true );
	$img = wp_get_attachment_image( $pid );

	if ( ! empty( $img ) )
		echo( $img );
?>

<h3>Extra profile information</h3>

<table class="form-table">
    <tr>
        <th><label for="Upload">Upload</label></th>
            <td>
                <input name="profile_photo" type="file" id="profile_photo" value="" />
            </td>
</table>

<?php
}

add_action( 'personal_options_update', 'save_user_custom' );
add_action( 'edit_user_profile_update', 'save_user_custom' );

function save_user_custom($user_id){

	if($user_id == false)
		return false;

	// If the upload field has a file in it
	if(isset($_FILES['profile_photo'])){
		if(!function_exists('wp_handle_upload'))
			require_once(ABSPATH.'wp-admin/includes/file.php');

		// Get the type of the uploaded file. This is returned as "type/extension"
		$arr_file_type = wp_check_filetype(basename($_FILES['profile_photo']['name']));
		$uploaded_file_type = $arr_file_type['type'];
		// Set an array containing a list of acceptable formats
		$allowed_file_types = array('image/jpg','image/jpeg','image/gif','image/png');
		// If the uploaded file is the right format
		if(in_array($uploaded_file_type, $allowed_file_types)) {
			// Options array for the wp_handle_upload function. 'test_upload' => false
			$upload_overrides = array( 'test_form' => false );

			// Handle the upload using WP's wp_handle_upload function. Takes the posted file and an options array
			$uploaded_file = wp_handle_upload($_FILES['profile_photo'], $upload_overrides);

			// If the wp_handle_upload call returned a local path for the image
			if(isset($uploaded_file['file'])) {

				// The wp_insert_attachment function needs the literal system path, which was passed back from wp_handle_upload
				$file_name_and_location = $uploaded_file['file'];

				// Generate a title for the image that'll be used in the media library
				$file_title_for_media_library = 'your title here';

				// Set up options array to add this file as an attachment
				$attachment = array(
						'post_mime_type' => $uploaded_file_type,
						'post_title' => 'Uploaded image ' . addslashes($file_title_for_media_library),
						'post_content' => '',
						'post_status' => 'inherit'
				);

				// Run the wp_insert_attachment function. This adds the file to the media library and generates the thumbnails. If you wanted to attch this image to a post, you could pass the post id as a third param and it'd magically happen.
				$attach_id = wp_insert_attachment( $attachment, $file_name_and_location );
				require_once(ABSPATH . "wp-admin" . '/includes/image.php');
				$attach_data = wp_generate_attachment_metadata( $attach_id, $file_name_and_location );
				wp_update_attachment_metadata($attach_id,  $attach_data);

				update_user_meta( $user_id, 'profile_photo', $attach_id );

			}
		}

	}

}