Joan -
When I "test" that scenario with the description on the left side and the images on the right, it comes up just fine.
As a suggestion for the time being, you can fix the look on the already posted listings.
Go to your Saved Listings, open each of those listings to edit them (one at a time) by marking the box next to them and then clicking the Edit button. When the listing opens on the lister page, scroll down to the template section and click Modify Layout. You can change the layout and preview it to make sure it will look right. Then you should save the listing with the changes.
Go back to the Saved Listings page and check the box again next to the listing and click the Get HTML button. Copy that HTML and take it to eBay to the "Revise listing" link for that listing. Drop in the new HTML and you should have a normal looking listing.
It sounds like a long process in writing but it shouldn't take you but a few minutes. In the meanwhile, we will take a peek at the code and figure out what is happening and get right back to you.
Thanks - Cara