code: protected void processIcons(ArtifactMetadata amd, RepositoryResourceWritable res) throws RepositoryException {
          String current = "";
          String sizeString = "";
          String iconName = "";
          String iconNames = amd.getIcons();
  
          if (iconNames != null) {
              iconNames.replaceAll("\\s", "");
  
              StringTokenizer s = new StringTokenizer(iconNames, ",");
              while (s.hasMoreTokens()) {
                  current = s.nextToken();
                  int size = 0;
  
                  if (current.contains(";")) { // if the icon has an associated
                                               // size
                      StringTokenizer t = new StringTokenizer(current, ";");
                      while (t.hasMoreTokens()) {
                          sizeString = t.nextToken();
  
                          if (sizeString.contains("size=")) {
                              String sizes[] = sizeString.split("size=");
                              size = Integer.parseInt(sizes[sizes.length - 1]);
                          } else {
                              iconName = sizeString;
                          }
                      }
  
                  } else {
                      iconName = current;
                  }
  
                  File icon = this.extractFileFromArchive(amd.getArchive().getAbsolutePath(), iconName).getExtractedFile();
  
                  if (icon.exists()) {
                      AttachmentResourceWritable at = res.addAttachment(icon, AttachmentType.THUMBNAIL);
                      if (size != 0) {
                          at.setImageDimensions(size, size);
                      }
                  } else {
                      throw new RepositoryArchiveEntryNotFoundException("Icon does not exist", amd.getArchive(), iconName);
                  }
              }
          }
      }
docs: Process icons from the properties file
  
  @param amd
  Metadata
  @param res
  Resource to add icons to
  @throws RepositoryException