How To Stop Pics Being served from Alicdn

All products I have uploaded via the plugin in the product description area on top of back end have been served by Alicdn. It slows the site tremendously. Why is it that the program is set up to do this and not just serve them from the media library? All you have to do to see what I'm talking about is to hit the text tab on the description area and you will see the pics are being served from Aliexpress CDN. How can we change this? Screen Shot 2018-06-14 at 3.53.34 PM.png