WYSIWYG - Image Position Not Being Applied

When using the WYSIWYG controls to position an image, it visually updates in the field but does not remain when you save, it seems to strip out the css, such as style="float: left; max-width: 390px; margin: 0px 10px 10px 0px;"
You can manually switch to code view and add this css yourself for now, but that's not ideal for clients etc of course.