The picture on this card is the father (the youngest in the picture) of the writer of this card along with his brothers, a cousin and his older sister. They were the children of immigrants with very low income. They are dressed in their best clothes (handed down one to the other) for a family event that would likely involve a baseball game later in the day. Being too poor to afford baseball bats, they are showing off their homemade bats (made from tree branches). It was an era when it was not uncommon to assume a serious expression when posing for a picture rather than smiling (particularly if one was older and trying to be more adult).
Card design:
Marketing Communications, The Tseng College
tsengcollege.csun.edu