This is the simplest idea - here it is not difficult to make a random repeat. I myself am a designer at Shutterstock and I know that plagiarism does exist - once in one or two months I write a complaint in Shutterstock to impudent plagiarists who copy my images. Here, for example - this is an accident can not be called (especially my picture was a long time in the top):
Damn that sucks. This is indeed to exact! :D
And I have a lot of such :-(