I am using feedburner (give it the url of my RSS feed). Each of my feed item have an image, is there a way to lower the actual image size so that people dont have to download the real size?

**EDIT FROM COMMENTS**

The url of the image is one of the item description. I resized it : 

    <img width="200" height="200" border="2" {{data['child']['']['image'][0]['child']['']['description'][0]['data']}} />

so that it has a smaller size.     
But then I realized that for mobile user we don't want them to download the original image which can be too big. That made me wonder what would be a way to reduce the size of the image before it is downloaded?