Watermark on hotlinked images?

Question

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!

Answer 1

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/

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.

Answer 2

You would need to check that the referrer HTTP header matches your site's domain prior to running the watermarking code to determine whether a watermark is required.

Answer 3

You can't do that with JQuery, since it is not at all involved when the image is served via hotlink. You'll need to do it server-side.

Answer 4

You would have to do something on the back-end to add a watermark to hot-linked images.

Check out this article if you have access to PHP.