Run across this text link in cj within a merchant: <a href="http://www.xxx.net/click-xxxx" target="_top"> 10% off all xxx </a> <img src="http://www.xxx.com/image-xxxxx" width="1" height="1" border="0"/> HTML: is the second part an image cookie?
Yeah, it looks like a pixel used to track impressions, like hitboy says. Nothing to worry about and you can remove it too if you want without doing any harm to your conversions.
Just make sure its ok with the advertiers to remove it if you do. I heard of cases where its against the tos sometimes.
Since CS is used to get visitors stuffed without clicking, I'll try this code to see if it functions like this.