Facebook Like Button Open Graph Help

I have a client Facebook app I created and there are 8 products listed, each with it\'s own page for each product. I am trying to get the right image to show up on the users Wall on Facebook when the \"Like\" button is clicked. I have put in a \"link_rel\" as well as an \"og:image\" tag in my meta data but I cannot get Facebook to select the right image. Not sure if this is a caching issue or not but I have given up. Can you help?