I wonder if its possible to have a watermark on hotlinked images on an external site, but not on the original site? I'm using jQuery, can I do something about this?
Thanks heaps!
This is not possible through a client-side technology. You will need to go server based.
If you have access to a server side technology, such as ASP.NET; you could expose all of your images through an ashx handler. This would let you display a water mark on some images, or not display images at all depending on the source.
Here's a great article on writing ashx handlers for images -- http://dotnetperls.com/ashx-handler/ https://web.archive.org/web/20160311222240/http://www.dotnetperls.com/ashx-handler
If you are using a *nix based server, @Jojo has some links for using php to similar effect.
After writing such a handler in ASP.NET or php, you'll need to check the HTTP Referer to see if it is a page on your site, or a third party site and then do the necessary image processing to produce your watermakr effect.