Greetings,
You did say that the photo was a Boxer Rebellion photo. I shared info on why it may not be. Now, you have changed the time reference to fit your argument There is one glaring difference in the photo and it is the upper lip. The soldier does not have the "v" in his upper lip as with your ancestral photo (time will not smooth that out). And his eyes are more recessed, causing his eyebrows to cast a shadow. I can tell how excited you are about this. Take a good look at the upper lip.
I know how difficult it is to find photos of your ancestors. And they do have a way of finding you, even when you are not expecting them.
Good Luck with your research.