Photgraphs of Rita Moreno as a child seem difficult to find. Searches of Google (www.google.com) and of Bing (ww.bing.com) turned up various photos of Moreno as a young woman, but I spotted none of her as a baby or child.
She discusses her performances as a child in the interview posted below, but the print version of interview contains no childhood pictures.
A book for young readers titled Rita Moreno: Shining Star might presumably contain a childhood photograph. The book is listed at Amazon.com but is not listed in the Library of Congress catalogue.
Other biographies of Moreno (who surprisingly seems not to have authored an autobiography) might be expected to contain childhood photos.