After updating my C2 to r71 release i got a message where it was explained that File preview will be removed in future.
I use C2 in all its futures except one little thing. I don't know why but in my pc i can't see the preview of my projects in HTTP mode.
I got this message every time :
<img src="http://i42.tinypic.com/1q1idj.png" border="0" />