images in rss feeds

ok so i finally figured out how to publish my own RSS feeds (with a little bit of help). I am now trying to put images into the rss feeds. I managed to do this using the http://www.w3schools.com/rss/tryrss.asp?filename=rss_ex_ thing and it works in their try it yourself preview thing, but it doesn't work in the rss block on Dolphin. Why is this?

This is the simple code i am using......

so is there a way to do it?