How to hide images from certain source via css

How to hide images from a certain source via css

In a project i had some pictures that were thrown in from the Backstretch Module.
As i didin´t want the pictures at that place and could not just simply display:none for all img tags i asked myself if there is a possibility to hide images via css based on their source.

And this is what works: div.thumbnail a img[src*="sites/default/files/backstretch/"] {
     display: none;