chebum

<a href="http://visualwatermark.com/wp-photo-protect/" rel="nofollow ugc">Photo Protect</a> adds an invisible layer over your post images to protect them from copying. 
Visitors trying to save an image will get a blank image instead of your photo.
Here is why you should download it:
<ul>
<li>Protects your images. 9 out of 10 visitors won’t be able to download and copy your images.</li>
<li>Works in every modern browser. No plugins required!</li>
<li>Has no dependencies. Correctly works with every framework your theme may have jQuery, MooTools, ExtJS, GWT, etc.</li>
<li>Supports responsive themes. Applies protection in a way both theme and protection layer continue to function properly. Even if your visitor resizes her browser.</li>
<li>Works on smartphones.</li>
</ul>

Photo Protect

Adds an invisible layer over your images to protect them from copying.

Scott Werner

By default, WordPress links images to themselves. A user sees that the image is a link, clicks it and they are then taken to a page of just the image. Then they click ‘back’ in their browser or move on to another site.
You could manually remove the link, but that is a pain. Plus, when handing sites over to clients they shouldn’t have to remember to remove it to have a great functioning site.

No Image Link

Defaults the Image Link option to 'none' when adding a picture to a page or post.

Photo Protect vs No Image Link