The challenge does not give any hints in particular and we only get the following jpg file

A rubber duck image given in the challenge

By doing a simple file command on the image we get the flag CTFlearn{ILoveJakarta}

$ file RubberDuck.jpg
RubberDuck.jpg: JPEG image data, JFIF standard 1.01, aspect ratio, density 72x72, segment length 16, comment: "CTFlearn{ILoveJakarta}", progressive, precision 8, 1536x2048, components 3