These thematic pictures of Животные are analogous to a visual dictionary. The theme "Животные" splits into several parts. For children, especially toddlers from 1 to 5 years old, it is better to divide the sets of cards over several days, or even weeks, so the information is absorbed better. Especially it is true if you are using flashcards to learn the russian language, which is not your native language.
To expand your russian language vocabulary on the "Животные" topic, flashcards games are the best way: