} else {
                proxy = Proxy.NO_PROXY;
            }
            propMap.put(HTML_PROXY, proxy);
        }
        return proxy;
    }

    String getThumbnailHtmlImageExcludeExtensions();

    default boolean isThumbnailHtmlImageUrl(final String url) {
        if (StringUtil.isBlank(url)) {
            return false;
        }

     * comment: File extensions to exclude from thumbnail generation.
     * @return The value of found property. (NotNull: if not found, exception but basically no way)
     */
    String getThumbnailHtmlImageExcludeExtensions();

    /**
     * Get the value for the key 'thumbnail.generator.interval'. <br>
     * The value is, e.g. 0 <br>
     * comment: Interval for thumbnail generator.