How does Flickr prevent people from downloading images from the site?

Question

Just wondering how does Flickr prevent people from downloading images from its site? What are they using?

Answer 1

Transparent .gif over the image. You can still download the actual image by viewing the HTML source and finding the image's actual URL.

For example, a random image: http://www.flickr.com/photos/34285128@N00/4300352607/

<img style="position:absolute;top:0px;left:0px;display:block" src="http://l.yimg.com/g/images/spaceball.gif" alt="" width="500" height="366">

That's the transparent image on top.

<img src="http://farm5.static.flickr.com/4057/4300352607_edcc5a4a9e.jpg" alt="Say It With Flowers by *sido* (back in a few days)." title="" width="500" height="366" class="reflect">

That's the actual image, which is displayed below spaceball.gif.