Post image in Feedburner email

I’m new to blogging, let alone WordPress, but I’ve succeeded in getting the site up and I’m starting to use Feedburner to send out email summaries of my posts to subscribers. Problem is that in the email (I’m using Outlook 2003) the thumbnail image that I attached to one of my posts overlaps the text.

I don’t understand why the image isn’t positioned the way I set it in the post on my blog. What can I do to make the image position consistent between the blog post and the email summary? (I’ve searched the support section at Feedburner, but haven’t found anything.)