code: static void dataUri( CssFormatter formatter, byte[] bytes, String urlStr, String type ) {
          if( type == null ) {
              switch( urlStr.substring( urlStr.lastIndexOf( '.' ) + 1 ) ) {
                  case "gif": 
                      type = "image/gif;base64";
                      break;
                  case "png": 
                      type = "image/png;base64";
                      break;
                  case "jpg":
                  case "jpeg":
                      type = "image/jpeg;base64";
                      break;
                  default: 
                      type = "text/html";
              }
          } else {
              type = removeQuote( type );
          }
  
          if( type.endsWith( "base64" ) ) {
              formatter.append( "url(\"data:" ).append( type ).append( ',' );
              formatter.append( toBase64( bytes ) );
              formatter.append( "\")" );
          } else {
              formatter.append( "url(\"data:" ).append( type ).append( ',' );
              appendEncode( formatter, bytes );
              formatter.append( "\")" );
          }
      }
docs: Write the bytes as inline url.
  
  @param formatter current formatter
  @param bytes the bytes
  @param urlStr used if mime type is null to detect the mime type
  @param type the mime type