reSmush.it is a free image optimization API. It compresses the size of your images, making them — and therefore your website — significantly faster to load. reSmush.it image style optimizer is a Drupal module that provides an image style effect with this image optimization capability.

Project page: https://www.drupal.org/project/resmushit
More info and demo: http://www.vacilando.org/article/resmushit

Because duplicate content is considered harmful for search engine optimization (Drupal SEO Group), if you are using Views, you should take steps to avoid duplication. For example, you should edit your robots.txt file (Google Webmasters/Site owners Help - > Dynamic pages, Google Webmasters/Site owners Help -> Duplicate content). If you have any exposed filters in Views, then the URL is full of variables. This leads to duplicate content and thus should be controlled via robots.txt (Google Webmasters/Site owners Help -> URL structure). In short if you use Views you need to use robots.txt! The following information will help in optimizing robots.txt for Google. Other major search engines and robots are covered here... via wikipedia cited source.