Enabling gzip compression for your pages on your website will not only allow your visitors to load the pages faster, but it might also be taken into account by google as a sign of quality (They encourage you to do so in the PageSpeed Insights of the Webmaster Tools). Here, I'm going to show you how to activate gzip compression on your domain in a Plesk configuration.
Today, I had a problem with the Yii Captcha widget. The image of the captcha was not generated correctly. The borwser showed sonething like this: