Do you really need to watermark? Alternatives?

[Vautrin]

Does that script prevent a visitor from seeing your source code?

Who cares about source code? Source code is is the instruction on how a broswer should render the markup language. It won't help them reconstruct an image. It may give them the filepath but unless they have FTP permissions then it won't help.

Most modern web browsers allow you disable javascript, and there are tools to get the info necessary to download the picture.

Your main defense this route is it's not worth the effort to do for most would be thieves, but don't kid yourself that a sophisticated attacker won't be able to get your images...

Of course, if you're a photographer with a sophisticated attacker following you then you've got bigger problems

 

[usayit]

Once you have a file path you don't need ftp to get the file as http serves the file anyways. At the most, you can disallow directory listings but once the file path is known... its over.

If you can see the photo... you can steal it. The best you can do is reduce the photo enough to make them less useful for enlargements.

 

[kkamin]

For Mac users all you need to do is:

COMMAND+SHIFT+3

to create a PNG snapshot of your entire screen.

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I use Windows too and downloaded a shareware app that does the same thing.

 

[usayit]

Command shift 4 is even easier

 

[StillImage]

https://www.digimarc.com/ , what I use, has found it very useful and if you do enough business it is worth the cost.