title: Why do web sites replace unicode chars with images?
body: <p>Recently I installed the NoScript plugin in firefox to control the execution of javascript. I noticed that some websites use some fancy unicode charaters as place holders for images, which are replaced with images once I allow javascript. One example site is github.com, see the screenshot which was taken before I enabled javascript.</p>
  
  <p>What's the advantage of this instead of simply place the image directly in html or css?</p>
  
  <p><img src="https://i.stack.imgur.com/WRoxe.png" alt="Screenshot of a github repo with the fancy unicode chars are highlighted. I censored some stuff because it is not my repo..."></p>