Direct linking of images

Can someone please tell me how can I tell that someone is direct linking my images. Im getting worried that im reaching my bandwith limit due to this!

You would need to check your web stats through your hosting control panel.
You should also be able to disable hot linking images there as well.

Thanks for the quick reply. Currently, is says "Hotlink protection is currently Disabled". Do I enable this?

Also, what about is the ipn_main_handler.php?

You might want to read some htaccess tutorials about hotlinking - in my eyes hot linking is a good alternative way to advertise! -> Try this

The ipn_main_handler.php is for PayPal Instant Payment notification and will not use your bandwidth, unless a payment was made. (Just like a normal page request)

If you really have to worry about bandwidth then you might take a look around - there some certified zen-cart hosts listed on the site. I am also spezialized in zen-cart hosting.