Sorry for being so thickheaded.
When you insert an image in a post or page the Image Uploader gives you 3 options for the Link URL, None, Image URL or Attachment Post URL. Select the last one to have the image open in a separate page that uses your theme template. You only can set that option easily after you've uploaded the image.
The Gallery shortcode can be modified in the Text Editor to show only the image you wish like this
where 1273 is the image ID number. The default size is thumbnail, but you can again modify the shortcode to get a medium-sized image like this
[gallery include="1273" size="medium"]
The difficulty comes when you want that image to appear on the right rather than the default left, and wrap text around it. It requires additional HTML and a little inline CSS to do so.
More here on the Gallery in general. http://en.support.wordpress.com/images/gallery/