code: public void setImageUrls(final String... imageUrls) {
          if (imageUrls == null) {
              throw new NullValueException("imageUrls is null");
          }
          final StringBuilder sb = new StringBuilder();
          for (int i = 0; i < imageUrls.length; i++) {
              sb.append("url(\"").append(imageUrls[i]).append("\")");
              if (i < imageUrls.length - 1) {
                  sb.append(", ");
              } else {
                  sb.append(' ');
              }
          }
          setCssValue(StringBuilderUtil.getTrimmedString(sb));
          this.imageUrls = imageUrls;
      }
docs: sample code :-
  {@code backgroundImage.setImageUrls("Test.gif", "TestImage.png")} creates
  <code>background-image: url("Test.gif"), url("TestImage.png");</code>.
  For css3 syntax method please use
  {@code setImageUrls(UrlCss3Value... urlCss3Values)} method.
  
  @param imageUrls
  an array of backgroundImage urls, eg:-
  {@code backgroundImage.setImageUrls("Test.gif", "TestImage.png")}
  and the generated css will be
  <code>background-image: url("Test.gif"), url("TestImage.png");</code>
  @since 1.0.0
  @author WFF