Problem:
When managing photos for your ad (when you have multiple photos), and you choose to make a different photo your thumbnail for that ad, nothing changes.
Cause:
In the ManagePhotos.aspx.vb file, in the Page_load event, someone declared an adId variable that masks the public property adId. Therefore, when it is set in the following lines, it's the local scope variable and not the pages property that is set. So, when the user selects a different photo, the AdID (from public property) that goes up in the SetAdPreviewPhoto is never anything but 0 (there is never an adid of 0 in the database since it starts with 1). No error is encountered or raised.
Solution:
simply remove the declaration of the localy declared adId from the Page_load event of ManagePhotos.aspx.vb
I did add a line setting the property to 0 (zero) in its place.