From Janet Greig Smith March 2007. (janetgreigsmith@tiscali.co.uk):
Hi, My name is Janet Greig Smith (Bell) Yes my Great Uncle John did go to America at least twice and then went to live with his nephew Andrew Greig and his wife (Mary Gray McMinn) and their children William, Janet and Margaret (my mother) at the Glen Farm Nr. Shawhead, Dumfrieshire until his death in 1928. We have always known he went to America on two occasions and along with the photographic evidence I have sent, I think we have found the illusive Andrew Greig in the shape of ‘Old uncle John’.
I would be more than happy to share my history with others. See Janet's History >>

June 2003 Alec Gregg: This photo is more likely to be of John Gregg[P1781], a nephew of Jennet Gregg[P1569], and brother to Janet's Gregg Kelly[P237]. He was know to have visited Kansas  twice - in 1907 and 1913. The woman in the picture is Shannon Kelly's great aunt Belle(Isabelle Kelly Warren[P1724], Janet Gregg Kelly's[P237] daughter). John Gregg was an uncle to 'Belle'.

Reportedly a photo of Andrew Gregg[P264] a nephew of Jennet Gregg[P1569]. The woman in the picture is Shannon Kelly's great aunt Belle(Isabelle Kelly Warren[P1724], (Janet's Gregg Kelly's[P237] daughter).
From The History of Scotch Valley: 'Andrew who lived in Scotland visited in the homes of the Gregg's in America. He was the son of Andrew Gregg [P206], and Izabella McIlwraith [P208].
He visited twice. Andrew was a sheep herder.
His sister Janet[P237] went to America with her aunt Jennet[P1569] and later married John Kelly[P1595]'.

UPDATE 8 June 2004.
NOTE - Joan Fisher 2004: Andrew Gregg does not appear in Ivie's affidavit as a sibling, which makes me think he was really a grandson. These affidavits listed all the siblings living and dead because the shares had to go to the children of the dead.

NOTE - A D Gregg 9 June 2004 :
From write up of Scotch Valley sent by Shannon.
 '3. Andrew Gregg lived and died in Scotland, A son Andrew visited the homes of the Gregg relatives in America. He visited twice. He was a sheepherder in Scotland. His Sister Janet went to America with her aunt Jennet and later married John Kelly'

If the word 'of ' was left out, it would read: 'A son OF Andrew visited the homes of the Gregg relatives in America. He visited twice.
Perhaps another son of Andrew Gregg visited, and this would account for there being no record of a son named Andrew.

Jeff Higgins - June 2004: I have the following Census entries...
1841: Andrew, with parents and siblings George, Jannet and James at Balnahoin, Colmonell. John Coughtrie and family were nearby at Ligatchuk. The Kelly's (Alexander and Agnes) were living just over the border at Castle in Penninghame.

1851: Andrew with wife Isabella and children Agnes, William and John were at Laggan, Colmonell. Andrew was a shepherd.

1861: Andrew was a shepherd boarding at James Agnew's dairy farm, Troax, Colmonell
1861: Isabella with children Agnes, William, John, Marion, Janet, Ivy and Jane were at Cossamuck cottage, Colmonell

1871: Andrew with wife Isabella and children Janet, Ivie, Jean, Agnes and Sarah Isabella were at Daljorrock shepherd's house, Colmonell. Andrew and Ivie were shepherds.

1881:Andrew with wife Isabella and children John, Agnes and Sarah and his grandson John Burnett were at Daljorrock, Colmonell. Andrew and John were shepherds

I'm certain there was no son Andrew....
He couldn't have been born before 1855 as Janet was 5th born.
There is no known statutory birth or death entry. 
He doesn't appear with the family on any Census.
I have most relevant census entries for Andrew and Isabella's siblings (potential aunts and uncles), there are no "stray" Andrew Greggs living with any of them.
The affadavit (I would love a copy or transcript) does not mention an Andrew

I don't think it would be a grandson, John Burnett was the 1st born grandson (1874) and he wasn't a shepherd. There are only 2 grandsons called Andrew, one born 1881 and one born 1893, both too young to be the man in the photo 

I like your theory Alec, one missing "of" can make a lot of difference and it seems the only candidates that fit the bill are Andrew and Isabella's sons. All 3 of them were shepherds and they are all the right age to be the man in the photo so I checked the Ellis Island website and found the following...

John Greig, 56, arrived in New York aboard the "Caledonia" on 07 Jul 1907, he was on his way to see his sister Mrs Janet Kelly in Seneca. He was a shepherd and lived in Pinwherry, Ayrshire.

John Greig, 62, arrived in New York again aboard the Caledonia (superstitious perhaps) on 14 Apr 1913, he was on his way to see his sister Mrs Janet Kelly in Seneca. He was a shepherd and he gave his brother Ivan Gregg, in Ballantrae, as a contact.

These seem to be the only TWO occasions that John visited

I can't find a 1901 census entry for Ivie and family, at first I thought they may have visited the U.S. around that time, but there seems to be no Ellis Island entry for an Ivie Greig (or variants). Maybe I haven't looked hard enough for Ivie in the 1901. 

Could the man in the photo be James and his sister Janet Kelly?
Maybe Shannon has a pic of Janet to compare. Would appreciate your thoughts

Regards
Jeff 

Jennet Gregg born 1823 at
Barr Ayrshire
 - Died 1899 Kansas USA

From a Seneca newspaper 1899 - 'James Gregg living at his farm north of Seneca is the last living of a family of eleven: His sister Jennet[P1569] who made her home with him since 1875, died last Sunday evening-May 7, 1899. She was buried in the Scotch Valley Cemetery the following Tuesday. Mr Gregg was the youngest of the family, his sister now dead was next in age. The family were natives of the parish of Barr, Ayrshire Scotland. Miss Gregg who was the youngest was born in 1823, being at the time of death just passed 76 years of age. She lived in Australia 1858-1874, and came from there to America and Nemaha County via the old Scotland home in 1875. Brought up in the Established church of Scotland, she afterwards joined the Free Church of Scotland. On the formation of the Scotch Valley Presbyterian Church she joined that and lived the balance of her days in membership.

The funeral was at the Gregg house, the service was under the direction of Rev. C.H. Bente of Seneca; singing was under the direction of James Fisher, who with his wife Carrie down from Pawnee City to attend, and show love for their old neighbor and relative.

The Psalms were used for the songs, and the general participating in the singing by the congregation showed an old time love for this old time love for this neighboring love, born of old acquaintance with the deceased. In the Cemetery the funeral took the form of a reunion to many, as friend after friend passed the tombstones of those long since "gathered to their Fathers", and whose life time was recalled and the days of "auld lang syne" came back to memory. Scotch Valley has always been noted for its neighborhood affection and hospitality. A funeral occasion like the death of Miss Gregg brought an opportunity of the old-time good cheer that is so much a part of the old Scotch life.

All friends from a distance were invited to remain for dinner. Three large tables were spread at the house and these were seated three times before all who had accepted the invitation to dinner were seated. 

Miss Gregg will be missed more than any other in the old neighborhood gatherings. She was the life of the Valley and none could match her in good cheer and joking. But, in it all she was a devout, matter-of-fact Christian who believed every word of the Bible just as it is written. 

Her vitality was wonderful and remained until the last. She had been sick during the winter but with return of spring she was up and about again, and uncle "Jim" often remark that his sister would yet outlive him. But exposure to the weather last Friday brought her down again. Peace to her ashes!'