The small symbol you see at the beginning and end represents a missing image (one the browser can not find). In the source code for the initial image you have:
Whereas the images are generally under the form:
This doesn't mean you can not have an image in the given location but unlikely in this case and in either event, not available. I did quickly check by swapping out the initial image for an available one and problem cured.
Quite likely the image at the end is the same issue. This is in a sense the same image referenced in a different way i.e. /test/oxford/picture0.jpg and still not available.
Once you have both situations pointing to the right location and available images, may be okay.