How to display posts side by side

My blog is http://libraria-kobi.blogspot.com
The question is: How can I display the posts side by side, like in this teplate (http://sight-soratemplates.blogspot.com), but using the Watermark template provided by Blogger (which is currently live on my blog, with small modifications made by me)?
You must understand that the main goal here is to display only the posts' images on main page (index) side by side, and the sidebar on individual posts, just like in the example.
Any ideas on how to show only images (without text) on the main page without using the <--more--> tag in posts would be also appreciated...