Thank you so much everyone for interest and thoughts on this photo.
I think I am tending to "Texas", though still not entirely convinced. Very interesting about the tie. I didn't know the differences in the way stripes went indicated anything in particular.

Would an American soldier be nursed in Australia during WWI? Although, there is nothing to indicate he was a soldier, just the date.
Definitely creases in the photo, not scars through his forehead, though as Ian says, there could be one above his eye.
As an aside, does anyone think this may be the same man? I have no indication who, where or when this was taken, other than it appears to be on a ship. (Might try to scan it again to see if I can get it any clearer, I realise it's not very sharp.)