/** Set alt, title and description for image uploads */
function set_image_meta_upload( $post_ID ) {
	if ( wp_attachment_is_image( $post_ID ) ) {
	$my_image_title = get_post( $post_ID )->post_title;
	$my_image_title = preg_replace( '%\s*[-_\s]+\s*%', ' ',
	$my_image_title );
	$my_image_title = ucwords( strtolower( $my_image_title ) );
	$my_image_meta = array(
	'ID' => $post_ID,
	'post_title' => $my_image_title,
	'post_content' => $my_image_title,
	);

	// Set the image Alt-Text
	update_post_meta( $post_ID, '_wp_attachment_image_alt',
	$my_image_title );
	// Set the image meta (e.g. Title, Excerpt, Content)
	wp_update_post( $my_image_meta );
	}
}
add_action( 'add_attachment', 'set_image_meta_upload' );