If your photos do not appear at all in the listing details page or photo slideshow, it is possible the browser you are using does not have flash. This is also true of most mobile phones as well. In this case, you will not see any trace of the slideshow feature.

Another possible cause is the incorrect photo format, such as .BMP format, or an invalid file name. This would cause those photos to not appear. If they are all incorrect, no photos will appear, but you will see the slideshow scroll through blank photos, some which may be correct, while others may be incorrect.