If he had brothers, or a father or son who also enlisted, they would try to have a group photo taken. This was not always possible, as leaves for individual soldiers might not be in the same time period.
Many portrait studios such as Eatons, had template mats to enclose the photo. These mats were pre-printed had spaces to fill in the soldier's name, sometimes his unit plus other details.
These mats were often brightly coloured with the words "For King & Country" or "For Service in the Great War" (it varied). Ornate frames could be purchased which had the same wording. Sometimes there would be a Canadian Maple Leaf at the top which 'stuck up' beyond the edge of the frame
If there is no photographer mark on the photo (back or front) there are clues that might help you determine a date and place.
Determine whether or not the soldier is in a Canadian or British uniform. Both Canadian and British uniforms were used by the CEF (Canadian Expeditionary Force). Men were usually issued a Canadian uniform when they enlisted, and they kept this for everything done in Canada. After they arrived in England the Canadian uniform would almost always be switched for a British one. (The reason for this switch was that the British uniforms were better quality and lasted longer)
Here are a few of the differences that might help you determine if the uniform is Canadian or British:
1. Canadian uniforms had 9 buttons on front (7 on the actual front and 1 on each front pocket) but the British one had fewer, and they were larger. There is an exception to this - if the soldier was in a Canadian Highland Regiment, his top sometimes just had 7 large buttons
2. Canadian uniforms had pointed cuffs, the British had straight (horizontal)
3. Canadian uniforms (except for the Highland ones) had stand-up collars, British uniforms did not.
So, if the soldier was in a Canadian uniform for this photo, there is a very good chance it was taken in Canada. It could also have been taken soon after arrival in England (before he was given his British uniform)
If he was in a British uniform it was almost certainly taken in England or in France. There were studios in France, behind the lines, where men could have their pictures taken to send home.
There is also a chance that the photo could have been taken on his return home from the war but this is not likely because the norm was for these photos to be taken before war's end and generally before going overseas.