I managed to spend a little more time with Yahoo! Pipes (previously). They now have a “badge” options, that makes it a lot easier to publish the results of your pipe on the net. See above for the result of an “image badge”.
If you should want to make one for yourself. It is important to have the “media:content.url” attribute set on all of your feed items. Else Pipes will not recognise your feed as hacing images. If you are using sources like Flickr, this will all be done for you. But if you are creating your own feed, you might need to pay attention to that.
When all else fails, you can always take a peak at my current ResidentAdvisor pipe for inspiration.