Suppose that you have the following image:
<img src="myimage.jpg" width="500" height="250">
and you want to protect it.
The solution is the following:
<img style="background-image:url(myimage.jpg);"
src="data:image/gif;base64,
R0lGODlhAQABAIAAAP///wAAACH5BAEAAAAALAAAAAABAAEAAAICRAEAOw=="
width="500" height="250">
