After I posted a recent post, I noticed that there was one client accessing an image about every 3 seconds. This was the referrer:
It looks like mod_pubsub is causing this traffic. mod_pubsub is an interesting project. it looks like the goal of the project is to create a "realtime" browser. It will automatically update the contents of a browser as content changes, without requiring a reload.
This is a great idea, especially if you want to be see the latest information such as stock values or news. Their demo hooks up with Syndic8.com to get the latest content from rss feeds. The one probelem that I see with this is when someone has setupt their web browser not to cache images. Then everytime that an update occurs, it will pull all of the images that are currently on the page.
It seems like mod_pubsub could fix this problem by only including the link to the images the first n times that the entry is displayed on a page.