Pictures suddenly appeared in My Files, help!

[Rikku Watro]

I just downloaded Gardenscapes on my phone about 3 weeks ago on my S4, and when I was checking my files, I found a picture called "NotEnoughStars" which was in the My Files app, but not in the Gallery app. It showed a picture of Gardenscapes and the words "Not enough stars!" in different languages. I deleted it, but I'm worried that something might be injecting pictures into my phone. Help!