Alan Keith has the best information on this image;

"This famous painting by Richard Waitt (1714) shows 'The Piper to the Laird of Grant'. A fully developed piob mor (Great Highland bagpipe) with all three drones is shown here, albeit with the two tenor drones set into an older style fork-shaped stock. I've been told by another piper that has seen the painting first hand, that the wood appears to be laburnam, but my guess is that it is some kind of dark fruitwood such as plum. The instrument seems to be mounted or decorated with lead or tin inlay, and the turning style is similar to other British and Continental varieties of the same period. Judging by the appearance of a narrow-tapered bore in the chanter, my guess is this pipe would be a bit quieter and lower in pitch than the more modern form of the instrument as we know it today."