Apropos, perhaps, of the discussion we were having on disappearing pictures, here is the copyright statement from a site that does not allow hotlinking.
Note the detail discussion the referenced page provides, on why the practice of hotlinking is "bad":
The problem, often, is that linking only to a large page full of images is a drink of water from a firehose to a viewer, rather than an immediate inline image that is relevant. Now that 'bandwidth' itself, and many aspects of hosting charges, have become relatively cheap, the 'secret agenda' is now that hotlinking does not serve page ads, or follow tracking metrics, for site owners that care about monetization.
I do think there are mechanisms that can be enabled to give metrics for 'views' of hotlinked images, and I am a little surprised that inline YouTube videos don't always contain the associated advertising that comes up when you select a video URL directly. So there may be technical solutions for at least some of the people who still look at hotlinking as the same kind of Web sin as failing to optimize your CLUTs.
Of course, there also has to be some understanding and opt-in from the user community, that being able to link to an image is a privilege and not expedience, and that a site owner is entitled to some recognition, or at least no out-of-pocket loss, for having hosted it for you. I would not object to putting a site link with each inline image (in case you want to see 'more' and incidentally engage a site's metrics and tracking).
Here is a picture of a N-3 from the steamlocomotive.com site
Photo courtesy Norman Hechtkoff