Carroll --

The family relationships described are wrong. Born in Smith County TN, Apr 4, 1828, Robert Jackson Armstrong appears on the 1860 census of Aberdeen, Monroe County MS. He raised a company called the "Red Rovers" which entered service of the State of Mississippi at Athens, Apr 29, 1861. This company entered Confederate service Oct 18, 1861, becoming Co "A", 5th Mississippi Regiment. Members received accouterments and equipment at Warrington FL, Nov 19, 1861, which included 4,000 buck-and-ball cartridges for their flintlock muskets.

During the Battle of Shiloh Capt Jackson was killed about 11:00 AM on Apr 6, 1862. This passage from the report of General Chalmers mentions Captain Jackson --

After this fight our ammunition was exhausted, and, the wagons being some distance behind, we lost some time before it was replenished. As soon, however, as the ammunition could be distributed we moved on, with the right resting on the edge of the Tennessee River bottom, with the same orders as before. When we had gone about a quarter of a mile we again encountered the enemy in a strong position on a hill with a deep ravine in his front, and a very stubborn fight ensued, in which we lost many gallant men, among them the Rev. M. L. Weller, chaplain of the Ninth Mississippi Regiment, a pure man and ardent patriot and a true Christian, and Capts. R. J. Armstrong and T. C. K. Bostick, of the Fifth Mississippi Regiment, who fell gallantly leading on their respective companies.

Official Records, Series 1 - Volume 10, Part I, p 549.

Regarding family relationships, Robert Jackson Armstrong was the son of John Barkley Armstrong. Born Sept 28, 1783, Surry County NC, JBA died July 20, 1836, Smith County TN. He had seven sons, among them Robert Jackson and John Barkley Jr. The family you described was that of John Barkley Armstrong, Jr., born Jan 20, 1819. In 1850 his family appears on the census for Cannon County TN. By 1860 the family had moved to McMinnville, Warren County. JBA Jr and his family were still there in 1870, so they did not move during the Civil War.

JBA Jr died Dec 18, 1873 (date may be 1878) and is buried in Riverside Cemetery, McMinnville TN. The Texas Ranger you mentioned, JBA Jr's son JBA III, is pictured below. He was born Jan 1, 1850, Cannon County TN, and died May 1, 1913, Armstrong, Kenedy County TX. His marker can be found at Oakwood Cemetery, Austin Texas.

A word on images from the Civil War period. The art and science of making photographic images was quite new in the 1850s. Images of family groups did not become common until after the Reconstruction era. The best source for family images such as you requested would be other family researchers. Of course there are many on-line forums for researchers who may have pictures. About 80% of the family pictures I have for ancestors who lived in the 19th century came from family trees located in Ancestry. This morning while browsing Ancestry I happened upon two images of other sons of the original JBA. You would do well to look for yourself.