It's an extremely steep price for one cel (too steep for me), but this particular offer is pretty interesting as you get the full background for the original frame in separate layers.
...and you can even reconstruct the blown-up tower by removing the layers with the smoke and the hole and adding a layer with the door! Great behind-the-scenes-look at the process of shooting animation!
Below are the matching screen shots from the official DVD edition. Man, just look how faded and ugly these screen shots become when compared to the beautiful original cel (below bottom). I wonder if we'll ever see the Inspector Gadget series in a properly restored, CLEAR version.
I'd seriously re-watch every episode of the show right now if I had the chance to see them in the strong, fresh colors and clean lines which the above cel offers. Maybe one magical day in the future, we'll see such a restoration of the episodes happen...