The term "2nd-great grandfather" indicates the individual is your parent's great-grandparent, or your great-great-grandparent.

The difference between first cousins and second cousins lies in their common ancestor: first cousins share a grandparent, while second cousins share a great-grandparent.

Also worth reading: How can I find out more about the history and significance of a picture from my great grandfather? · How can I trace my family lineage back to my great great grandfather? · What was life like for my great grandmother and great grandfather around 1945?

Online platforms, such as Reddit, allow users to post photographs for restoration or share restored images.

Old family photos and portraits can be found on genealogy websites, historical society repositories, and family-run sites.

Google search is a powerful tool for locating family photographs online, providing access to countless resources.

MyHeritage's family relationship chart helps determine relationships: find your relationship to the common ancestor using the top row, and use the left column for the family member's relationship to the common ancestor; the intersection of the two provides your relationship with that relative.

Physical resemblance between ancestors and living relatives is common, as seen with the OP's 2nd great grandfather and cousin.

Online resources, such as the Arizona Project, can help locate ancestors' photographs, especially as older generations pass away and their materials become available online.

To count generations in a family tree, consider yourself and siblings as one generation, parents and their siblings as the second generation, and so on.

The formula for calculating ancestors in a given generation is 2^n (where n is the number of generations back from you and X is the number of ancestors in that generation).

Cousin relationships are defined by the number of generations away the common ancestor is: first cousins share a grandparent (2 generations), second cousins share a great-grandparent (3 generations), and so on.

FamilySearch is a resource for connecting with family, providing information on ancestors and assisting in building family trees.