Alignment and Text Wrap issue

I am working on the design of my blog based on the default theme. I have a basic page designed here
If you scroll down to the “big in japan” image and the “Real Enemy” image. I am trying to have the image align to the right with the text wrapping around the left side. I want the image flush align (on the right side) with the main text so I do not want to use the insert image button in the editor. I have tried to do this in CSS (class=”alignright”) but I can’t seem to make it work. The images just move slightly to the right (looks like an indent). Also, I do not understand the “img.centered” and “img.alignright” in the CSS of the default theme. What do they do and how do I use them? (I have tried, and they do not seem to do anything. But I am probably not using them correctly)