Family Histories

I was cleaning my basement out yesterday and found something really interesting.  It was packed away hidden behind a box on a shelf.  I found this picture.  At first glance I thought it might have been my grandfather on my dad's side.  He was an airplane mechanic during WW2.  However the time on the photo was much old, 1916. 

It turns out that my great grandfather on my mom's side was in the 100th overseas battalion during WW1.  This was a picture of his whole battalion.  It was originally at my great grandmothers house in Winnipeg.  Over the years it got moved to several houses and packed away.  Sadly we don't know exactly which soldier is my great grandfather.  He passed away in 1950 (32 years before I was born and even before my father met my mother). 

I would love to learn more about this battalion.  If anyone knows any good websites or sources, please let me know.