I think it's an issue with the way webshots hosts images. Those URL's don't go to an image file; they go to a dynamically-generated page that includes the image (among other things), but the image itself is displayed using Flash.
If you link directly to a JPEG, GIF, or PNG image, it should show up in-line.
On the webshots page for one of your photos, I see a section on the right titled "direct link to image" which has a URL that points directly to a JPEG, e.g.: Code:
They also have links to change the size of the picture you're linking to. If you choose a size, it will generate a URL you can use. Here's a test:
Hope that makes sense and helps. Just look on the right for the "link to this picture" section.