Fraudulent auctions are huge problem on Ebay - and they have hit the Hermes Birkin section in a big way. There are a very few sellers who specialize in selling authentic Hermes...and many fraudsters who try to copy them! Some have pictures of fake Hermes handbags in their auctions which look almost look real. Some have pictures of authentic bags which they never intend to send. Others use stolen pictures from other Ebay auctions or even Japanese sites (they think you won't be able to see the originals...).
There is no fool-proof way to protect oneself from these "sharks" but there are some basic rules to get started:
Avoid 3 day auctions - these are done on purpose to avoid getting noticed by Ebay. By the time Ebay figures out that the auction is illegal - the auction is already finished and the winning bidder can already been a victim.
Avoid all sellers with "private" feedback. The only reason to have private feedback when selling high ticket items is if one has something to hide...
If a price seems to good to be true, it probably is. Brand new and authentic Birkins cannot be found under retail, if someone is selling an Hermes bag for less than it costs in the store, they are fraudsters.