I dont think the picture can throw to much weight to your case unless it states that what is in the picture is the actual item.

Of-course, it matters if the seller shows photo of the real thing and then sends cheap replica.  In any case it is the other way around, seller on eBay should mention in their description if the item in photo is NOT the actual item you will receive.  The photo is part of the description.

Which ever way you look at it, selling fakes is a criminal offence.