You shouldn't need to do any thing like:
<div style="text-align: right; margin-left: auto; margin-right: 0; width: 100%;"><img class="right" src="assets/MyImage.JPG" alt="test" title="test" width="100" height="100" /></div>
The point of using a CMS, such as SilverStripe, is to be able to create web pages without having to use any code whatsoever.
You need to put:
in your template somewhere, in the theme that you are using (not the tutorial theme)
If images are wrapped in a div that has the class typography then everything should work fine.