The Irish Traditional Music Archive has digitised the illustrations from Francis O'Neill's publications. O'Neill's various books contain the largest pictorial collection illustrating Irish music made until his day; many of the images would not exist if he had not commissioned them.

Check out the links below

http://www.itma.ie/VisualMaterials/irishFolkMusic.html

http://www.itma.ie/VisualMaterials/O%27NeillIllustrations2.html