These largely comprise of family photographs, including photographs of Thomson's immediate family as well as both he and Lady Thomson's ancestors, but also contain images regarding Thomson's career and achievements.

Photograph of a group of men judging Shorthorn cattle at the Royal Dublin Society's Spring Show at Ball's Bridge, Dublin, Ireland on 25 April, 1905.

Photograph of the chestnut thoroughbred stallion, "Red Prince II" that was foaled in 1889 that was the champion at the Royal Dublin Horse Show, 22-25 August, 1905. The horse was bred by A E Linde, Eyrefield Lodge, Kildare and was the property of William Pallin of the Athgarvan Stud in Curragh Co. Kildare.

Photograph of the Thoroughbred stallion, "General Peace" standing in a field in the early 20th century. His sire was "Gallinule" and his dam was "Moira" by "Victor" and he was the property of Mrs. A.M. O'Callaghan. He won first prize at the Royal Dublin Horse Show, 23-26 August, 1904.