Great for toddlers. And it's free. What do you have to lose?
I've downloaded many free flash card apps for my 18 month old, and this is the best. Every picture does something when you tap it, and it's one of the few apps he can use correctly entirely by himself. They also have a Chinese version available with the same pictures, which is great for us because we're in a bilingual household. I'm happy enough with the free one that I will buy some of the others from this company, and I don't usually buy apps.