loadImage(img, url, limit - 1);
        }, IMG_LOADING_DELAY);
      } else {
        $(img).parent().parent().hide();
      }
    });

    imgData.src = url;
  };

  $("img.thumbnail").each(function() {
    var $img = $(this);
    $img.css("background-image", 'url("' + contextPath + '/images/loading.gif")');
    loadImage(this, $img.attr("data-src"), IMG_LOADING_MAX);
  });

### Log Files

Check these logs for troubleshooting:

- **Main Application**: `logs/fess.log`
- **Crawler**: `logs/fess-crawler.log`
- **Search**: `logs/fess-search.log`
- **Thumbnail**: `logs/fess-thumbnail.log`

### Getting Help

- **Documentation**: https://fess.codelibs.org/
- **GitHub Issues**: https://github.com/codelibs/fess/issues
- **Discussions**: https://github.com/codelibs/fess/discussions

      },
      "title": {
        "type": "text",
        "analyzer": "standard_analyzer",
        "search_analyzer": "standard_search_analyzer",
        "term_vector": "with_positions_offsets"
      },
      "thumbnail": {
        "type": "keyword"
      },
      "url": {
        "type": "keyword"
      }
    }

import org.codelibs.fess.helper.CrawlingInfoHelper;
import org.codelibs.fess.helper.LanguageHelper;
import org.codelibs.fess.opensearch.client.SearchEngineClient;
import org.codelibs.fess.thumbnail.ThumbnailManager;
import org.codelibs.fess.util.ComponentUtil;
import org.lastaflute.web.Execute;
import org.lastaflute.web.response.JsonResponse;
import org.opensearch.action.bulk.BulkResponse;

            public String getIndexFieldUrl() {
                return "url";
            }

            @Override
            public String getIndexFieldThumbnail() {
                return "thumbnail";
            }

            @Override
            public String getIndexFieldClickCount() {
                return "click_count";
            }

            @Override

                    return "filetype";
                case FessConfig.INDEX_FIELD_FILENAME:
                    return "filename";
                case FessConfig.INDEX_FIELD_THUMBNAIL:
                    return "thumbnail";
                case FessConfig.INDEX_FIELD_MIMETYPE:
                    return "mimetype";

                // Crawler settings
                case FessConfig.CRAWLER_DATA_SERIALIZER:

                                            key="labels.thumbnail"/></span>
                                    <div class="form-inline col-sm-9">
                                        <la:errors property="thumbnail"/>
                                        <div class="form-check">
                                            <la:checkbox styleId="thumbnail" styleClass="form-check-input" property="thumbnail"/>

									<filtering>true</filtering>
									<includes>
										<include>bin/fess</include>
										<include>bin/fess.in.sh</include>
										<include>bin/generate-thumbnail</include>
										<include>bin/plugin.xml</include>
									</includes>
								</resource>
							</resources>
						</configuration>
					</execution>
					<execution>

            public String getIndexFieldUrl() {
                return "url";
            }

            @Override
            public String getIndexFieldThumbnail() {
                return "thumbnail";
            }

            @Override
            public String getIndexFieldClickCount() {
                return "click_count";
            }

            @Override

            public String getIndexFieldUrl() {
                return "url";
            }

            @Override
            public String getIndexFieldThumbnail() {
                return "thumbnail";
            }

            @Override
            public String getIndexFieldClickCount() {
                return "click_count";
            }

            @Override