Okay I guess where the confusion is that I went to the same Tutorial and looked at 15, 16, 17 (16 17 cover something else).  I checked out 14.  In the tutorial he is using what I mentioned the backdrop.  Can you tell me how you are loading a background image that is viewable in the vertex modeling room then I can see if its happening on mine.  That and I would like to see how that works and where you are loading your images into.

When I load up the backdrop images they stay locked to the grid, when I pan using either the keyboard + mouse button or using the icons the screen moves the grid stays with the image.