Instructive Loading Image

I have noticed that when I show Blend4Web apps to people who have never seen them, they do not realize at first that they can scroll their view around. Everybody is used to a static 2D picture. Maybe you could take advantage of the player loading time to display an instructive image that lets users know they can interact with their mouse. Similar to the one that shows when you click on the "?" inside the player. Maybe there could be several options on which image to display depending on what camera setting are used.
I have been able to replace the image manually in the exported HTML file. I was wondering, does this loading image exist somewhere in the SDK so you could customize it to be part of every HTML export?

Yep, this can be a problem. For now we have the "autorotate" option which we hope helps a bit - the user sees a dynamic picture (like in the sunglasses example). We'll definitely think about what can be done here, thanks for suggestion!

Where is the autorotate setting? I see the button in the player after it loads, but is there an export setting to make it rotate automatically?
*EDIT*
Found it, you put ?autorotate after the URL:
http://williamwelker.com/b4w/sphere/sphere.html?autorotate