Why did an unknown photo named pwbg.jpg appear in my "Samsung Galaxy S4 zoom"?

[Android Central Question]

I had just updated my phone using Kies (Lite) and then I noticed this new picture (which I had not taken) in my Gallery in an album called 0 [zero ]. I had not created nor named this album. The picture depicts a locomotive with a cargo car at a railroad exchange.

 

[Rukbat]

Have you ever seen that picture on a website or inn an app?