Buzz,
This is what I found out so far. The 108th Bn is not perpetuated by the Queen's Own Cameron Highlander's of Canada, but many members of the 108th Bn did serve with the Camerons in WW1. The 108th Bn was recruited and then sent to England, and there was utilized as a 'holding' unit (for lack of a better term) while personnel were sent to various units as reinforcements. Our regimental records indicate that many members of the 108th Bn were sent to the 43rd Bn (Queen's Own Cameron Highlander's of Canada), and served for the remaining duration of WW1 with the 43rd Bn.
The uniform in the picture is definitely a Cameron Highlander's uniform, and the Queen's Own Cameron Highlander's of Canada were the only Canadian unit in WW1 to wear that uniform and regimental accoutrement's (Camerons of Ottawa did not 'exist' as a highland unit at the time). There are only two plausible scenarios that the RSM and I can think of as explanations:
1) Your family member enrolled with the 108th Bn, but was then sent as a reinforcement to the 43rd Bn, and the picture was taken after the transfer; or
2) Your family member was a member of the Queen's Own Cameron Highlander's of Canada prior to WWI, but was recruited into the 108th Bn.
Perchance was your family member from the Selkirk Manitoba area? The RSM did indicate that our unit had a small detachment in Selkirk prior to WWI, and the 108th Bn apparently recruited heavily in that area. Maybe he was a Cameron before the war, or was later transfered to the 43rd?
I'll let you know if we come across any other info. Another option would be to PM me the family member's particulars and any other info, and we can see what we can dig up. Cheers.