code: public ResultList<Artwork> getCollectionImages(int collectionId, String language) throws MovieDbException {
          TmdbParameters parameters = new TmdbParameters();
          parameters.add(Param.ID, collectionId);
          parameters.add(Param.LANGUAGE, language);
  
          URL url = new ApiUrl(apiKey, MethodBase.COLLECTION).subMethod(MethodSub.IMAGES).buildUrl(parameters);
          String webpage = httpTools.getRequest(url);
  
          try {
              WrapperImages wrapper = MAPPER.readValue(webpage, WrapperImages.class);
              ResultList<Artwork> results = new ResultList<>(wrapper.getAll(ArtworkType.POSTER, ArtworkType.BACKDROP));
              wrapper.setResultProperties(results);
              return results;
          } catch (IOException ex) {
              throw new MovieDbException(ApiExceptionType.MAPPING_FAILED, "Failed to get collection images", url, ex);
          }
      }
docs: Get all of the images for a particular collection by collection id.
  
  @param collectionId
  @param language
  @return
  @throws MovieDbException