I am of the opinion that it might be Falkirk as the second on the left looks very much like the old Falkirk FC inside-left Alex Burt, but other than that I am stumped.
Alex Thomson's career as far as I know was St Ninians Thistle [????], St Bernards [1896/97-1897/98], Falkirk [1897/98-1901/02], King's Park [????] but I may have missed some of it out.
The flag might be a clue, but I can not really make out what flag it is, and the buildings in the background may shed some light if that is Brockville Park, of course it may be a completely different team altogether, if anybody could be of help please get in touch.