The photograph was taken by Gilbert photography in Frostburg, Maryland.
I think I have located the two men in the front row in the census records and Ancestry public family trees. On the reverse they are identified as Ben Filer and Bill Filer. The two young men standing behind them are "Hen" Filer and "Chill" Filer.
My first thought was that we had two fathers and two sons here, especially since the names of the older/younger counterparts rhyme. I've not been able to confirm that, however.
I first checked the census records and discovered that brothers Benjamin Chas. Filer and William Filer were born in Pennsylvania, but were living in Maryland in 1900. Benjamin was married by that time, but William was still living with their parents, Benjamin and Fannie. Father and both sons are shown as coal miners.
Moving over to the public family trees on Ancestry I discovered that Benjamin was born in September 1875, married in 1899 to Rachel Folk, and died in 1959 in Maryland. William was born in 1877, married in 1915 to Mary Duren and no information was available as to his death. While Benjamin has quite a few children listed, there is no likely candidate shown to be a son named "Hen", which I am guessing might be a nickname for Henry. Of course it could be a nickname for any number of reasons that have nothing to do with his actual name.
No one had any information regarding William's children.
But, in my opinion, this looks like two brothers and the next generation. I hope somebody knows their stories.