The shots were taken with a Canon 60D (APC sensor) with a 12mm lens. There were 12 shots taken at 30 degree increments.
The shot from Firefox that I posted was zoomed in quite a lot.
The Original Chair shot was not zoomed in as much because it is just one of the single shots (I cropped the top and bottom a lot - it was taken as portrait orientation. I only cropped a little from the sides).
When you compare the chair - which was centered it's a lot wider in Firefox.
I did the stitch in Autopano and the build in Panotour using the basic simple commands from the video tutorial - I didn't do anything fancy.
I noticed when I put the Firefox to full screen it just readjusts the "stretched" image.
I've tried a few different sets of pictures and I always seem to get the same result.
Also you can see how stretched the piano is - as I said, this shot from the build is zoomed in a lot.