I know he is a WWI soldier, but still, you people are very smart with war stuff. Is he Austrailian? He’s a very handsome young man. Any information would help, because I am entranced! Like ‘Somewhere in Time’! 
Thank you!
Collar Dogs and Hat are both uniquely Australian. Beyond that you’ll have to contact the person who uploaded the photo for more details.
What little information there is on this photograph is at what I think is the original public source here: http://www.awm.gov.au/blog/2008/11/11/awm-on-flickr-commons/
It was used on the cover of this book: http://www.bigskypublishing.com.au/bookview.php?iid=21&vt=B
This might be a more compelling version: http://www.flickr.com/photos/bancoimagenes/4569640246/
Hmm, yeah. even those websites say he is unidentified. It’s sad, especially for how handsome he is. I hope to find out soon… 
But thanks for you help everyone!