} catch (final Exception e) {
                logger.warn("Failed to process a thumbnail generation.", e);
            }
        });

        if (!idList.isEmpty()) {
            thumbnailQueueBhv.queryDelete(cb -> {
                cb.query().setId_InScope(idList);
            });
            thumbnailQueueBhv.refresh();
        }
        return idList.size();
    }