My information is that Thomas McVeety and Margaret McTavish were married in 1841 and had three children: Mary (1842), Thomas X. (1846), and James (1848). So, it does not appear that Margaret McTavish died when Mary was born.
The only info that I have on Mary McVeety is that she died 19 April 1909. If that death date is accurate, then the woman in the photo could be Mary (McVeety) Anderson. By the way, if you could provide me with info on her family and descendants, I would appreciate it.
Thomas X. McVeety moved to Polk County, Minnesota, married Isabella McDonald and had several children. I can provide more info if you wish. James McVeety lived in Bruce County, Ontario and to the best of my knowlegde did not marry.