It's really too similar to say that it isn't coming from there, but you can see that he made some work on the logo itself, it's not just a part. And can't we argue that he inspired just on the style of the socket?

In this situation I guess he'll have to contact the designer, confront him with the shutterstock image and hope for an explanation, but what will be the outcome of all this? And isn't it there an extended license to allow full rights of the image?