Naor,
LinkedIn is very finicky when pulling meta data from the page. If you want to be sure it's pulling the right image you have to add an img src tag in the head section.
Go to Edit Page Meta Tags>Custom HEAD HTML section on the landing page and add an
img src tag and
alt tag if you want users to have a choice of images.
Example:
<head>
<img src="http://go.kokopop.com/rs/mktodemo17/images/bucketList.png" alt="http://go.kokopop.com/rs/mktodemo17/images/bucketList2.png">
</head>