The fact that the tracking link is going through an image and not the actual link speaks volumes.
It is a way of getting everyone to do their SEO for them because Google will only see the anchor text of the link and where the link is going to.
So in the end this site will get the top positions in Google pushing affiliates out of the picture.
I wouldn’t promote them if I can’t do it through a straightforward link that I can track through a script.