Blog Button

So I'm not the greatest at all this blog techie stuff. I try to learn as I go. And I finally made a blog button! I think it should be working how it should! Let me know if you notice it doesn't work! For example... when I write this post the little box appears the right side but as soon as I hit publish it shows up way bigger! And my code changes to something and doesn't work. But... the correct code is over on the left hand sidebar <======== The code is for a smaller size picture. But on the blog I wanted to show a bigger size.  What do you think? Think it'll suffice?