The postcard shows a painting by Robert A. Alejandro entitled Life at Sea. I found a website of a "Robert A. Alejandro" but am not sure if he is the same person who did the painting. I just assumed that they are the same person. Award-winning Filipino designer Robert A. Alejandro offers a wide range of graphic design services from concept to completion. His projects include book and magazine design, including book cover art and illustration for children's books, coffee table books, art books and more.
I couldn't find additional information about the painting nor its location (private collection or museum).