The piggy bank's symbolism is obvious--saving money.
The pineapple might not be so well known as the symbol of hospitality to everyone, so here's an answer from our friends at answers.com:
The pineapple has served as a symbol of hospitality and warm welcome through the history of the Americas.
Christopher Columbus wrote the first account of a western encounter with the pineapple in the journal of his second discovery voyage across the Atlantic. He and his men landed on the Caribbean island of Guadalupe where the sailors enjoyed this sweet, succulent new fruit, which had already become a staple of native feasts and religious rites.
In 1493, Columbus first brought the pineapple back to Renaissance Europe that was largely devoid of sweet foods, including fresh fruit. The pineapple's exotic nature and sweetness soon made it an item that soon acquired both popularity and curiosity for centuries after its European arrival. For two centuries, as European horticulturists struggled to perfect a hothouse method for cultivating pineapples in Europe, the pineapple became even more a coveted commodity. In the 1600s, King Charles posed for an official portrait while receiving a pineapple as a gift.
In colonial America, hostesses would set a fresh pineapple in the center of their dining table when visitors joined their families in their homes. Visiting was the primary means of entertainment and cultural exchange, so the concept of hospitality was a central element in colonial life. The pineapple, then, symbolized the warmest welcome a hostess could extend to her guests, and then often it also served as the dessert for the meal. If the visitors spent the night, they would be given a bedroom with a bed in which pineapples had been carved on either the bedposts or the headboard -- even if that was the master bedroom.
Creative food display became a competition among the hostesses, because it declared her personality and her family's social status. Hostesses tried to outdo one another in creating memorable dining events. In larger, more affluent homes, the doors to the dining room were kept closed to create an air of suspense and excitement over the preparations of the hostess. Colonial grocers sometimes rented pineapples to hostesses desperate to create a dining experience above their financial means. Later, once that hostess had returned the pineapple, the fruit would be sold to more affluent clients who could afford to actually buy and eat it. Regardless of ones financial ability to actually buy and eat the pineapple, however, visitors to the homes that displayed the pineapple felt particularly honored that the hostess had spared no expense to secure one in their behalf.
By the Gilded Age, which was the era in which Samuel Couples lived, through the present day, the pineapple became a familiar symbolic image of welcome, good cheer, and warmth and affection between all who dwell inside the home.