This is your first blog entry. You see the div class directly above in your code? Ive made a blog DIV and a blog2 DIV. They are different. You are seeing 'blog'. blog is a blog entry that it doesnt matter how much words, pictures etc. you put it in, it will streth to accomadate whatever you put inside.
This is blog2. blog2 has a scrollbar attached. Meaning you can put whatever you want in it, but instead of stretching it will stay the premade size and a scrollbar will pop up if necessary. I would recommend using both for your blog.