wro4j-core/src/main/java/ro/isdc/wro/model/resource/processor/impl/css/DuplicatesAwareCssDataUriPreProcessor.java
@Override
  protected final String replaceImageUrl(final String cssUri, final String imageUrl) {
    if (!imageUrls.contains(imageUrl)) {
      imageUrls.add(imageUrl);
      return super.replaceImageUrl(cssUri, imageUrl);
    }
    LOG.debug("duplicate Image url detected: '{}', skipping dataUri replacement", imageUrl);
    return imageUrl;
  }
@Override
  protected final String replaceImageUrl(final String cssUri, final String imageUrl) {
    if (!imageUrls.contains(imageUrl)) {
      imageUrls.add(imageUrl);
      return super.replaceImageUrl(cssUri, imageUrl);
    }
    LOG.debug("duplicate Image url detected: '{}', skipping dataUri replacement", imageUrl);
    return imageUrl;
  }
Replace provided url with the new url if needed.

@param imageUrl to replace.
@param cssUri Uri of the parsed css.
@return replaced url.