wp_ajax_get_attachment

function wp_ajax_get_attachment() {
	if ( ! isset( $_REQUEST['id'] ) ) {
		wp_send_json_error();
	}

	$id = absint( $_REQUEST['id'] );
	if ( ! $id ) {
		wp_send_json_error();
	}

	$post = get_post( $id );
	if ( ! $post ) {
		wp_send_json_error();
	}

	if ( 'attachment' !== $post->post_type ) {
		wp_send_json_error();
	}

	if ( ! current_user_can( 'upload_files' ) ) {
		wp_send_json_error();
	}

	$attachment = wp_prepare_attachment_for_js( $id );
	if ( ! $attachment ) {
		wp_send_json_error();
	}

	wp_send_json_success( $attachment );
}