Thousands more paintings are to be added every month, with the aim of having the complete national collection (estimated at around 200,000 works) available within 18 months.
So far only one of the works of artists who lurk in distant branches of my family tree are in the online collection. John Northwood (1836–1902) is depicted in a handsome portrait by his son, also John.
You can search for titles and subjects as well. Perhaps there's a picture deemed collectable of a location in your family history.
I understand Library and Archives Canada plan to put the complete (?) collection of the National Portrait Gallery online. That collection contains "more than 20,000 paintings, drawings and prints, 4 million photographs, several thousand caricatures, and ten thousand medals and philatelic items." Will LAC adopt the same strategy of releasing the collection online gradually?