markerPromise = survey.deleteCustomSingleMarker().then(function() {
                    return FileHelper.saveFileFromPath(req.files.custom_single_marker_img.path,
                        'images/survey/' + survey.id + '/marker/custom_single_marker' + path.extname(req.files.custom_single_marker_img.name),
                        req.files.custom_single_marker_img.name);
                });