Prevent third party leeches. Stop other blogs from using your images directly.
Imaguard will see when one of your images is used on another domain. Unless you specifically white list the site, it will prevent the preview.
In non-aggressive mode Imaguard will redirect the visitor from the image file and show the image inside your normal blog layout.
In aggressive mode, Imaguard will fade your image out and out a text on top (f ex “Click to see”). Currently clicking images in Google Image Search redirects to the page where the Google Crawler found the image.
You may want to white list sites such as twitter.com and facebook.com.