This is almost certainly an Austro-Hungarian infantry private's uniform
During WWI, Tarnow was a part of Austria-Hungary, and mobilized Poles from that area into the army (including Polish Legion/Polish Auxiliaries).
The hat on the table in the corner resembles an infantry field cap. It has what looks like a feather sticking out of the top, which is a common feature of Austro-Hungarian mountaineers (although the individuals are not mountaineers, as they lack the flower collar insignia).
The belt buckle looks like the Dual Monarchy one.
Additionally, the shape of the cross and ribbon looks like a mobilization cross or long military service cross (or a similarly shaped medal such as the Austrian Iron Cross of Merit) worn in the Austro-Hungarian fashion high up on the chest.
The color of the ribbon is a little bit confusing because the Iron Cross of Merit was introduced in 1916, but is being worn with a solid red ribbon which is the rule for being awarded in peacetime (as far as I can tell, no other Austro-Hungarian cross-shaped award was properly worn on a solid color ribbon).
I have not been able to find an exact match for them (it seems that the collar and cuffs should be another color), but if someone unfamiliar with the uniforms had colorized them, they might not have known this (edit: from comments by OP this appears to be the case, as AI colorization is essentially guesswork).
The shorter gentleman is my great-grandfather. The only information I have is his name. I don't even have his DOB or DOD (although I'm speculating circa 1880's - 1940). My ancestry is all Polish so thus the assumption for Polish uniforms. I've also researched that medal and seem to keep coming back to the cross of valor that was introduced in 1920. Lastly, my family comes from South of Tarnow, Poland. Please see original image at imgur.com/a/ePZRfVO. Thank you!
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