I already have XAMPP installed locally, and I have used it extensively, so I know it works.
As mentioned previously, I unpacked 2.4.7 separately on my local machine and installed SS.
After opening http://localhost/ ... /index.php/admin/ I entered the CMS, created a new page, pasted some text as text in the tinymce window, and then inserted an image. The results were the same as on the Linux server.
In other words, to make the image display in the right position, I have to manually remove the div that tinymce puts around the image, which is:
<div class="captionImage right" style="width: 100px;">
I have verified the existence of <div class="typography"> in Page_results.ss and Page.ss in the blackcandy theme, which is the theme I am using.
HOWEVER ... if I leave the Caption Text field blank, the offending div tag is not inserted by tinymce, and the image is positioned correctly.