Well, there are a few things here that needs to be mentioned.
First of all, the editor, is just an editor ... It does not represent exactly how the page will look in your theme/gallery, because this is styled by a separate CSS stylesheet.
As for the text aligned to the RIGHT of your image, this is a problem with flash textfields and their weakness with text-aligning with images. It can usually be solved by using textformat:
<textformat leading="100"><img src="..." height="100" width="100" /></textformat>
The final problem I assume is related to height in line breaks and alignment? Are you using <br> (shift+enter) or new paragraph <p> (enter)? Perhaps you can give me link and login to your admin so I can take a look?