This was an assignment file that has been rejected before. The problem is "The image contains a large amount of noise artifacts. Please fix this issue using noise-removal software and resubmit."
Unfortunately, the assignment was closed by that time. Anyway, after I fixed the problem, then I resubmit it as regular file and now it has been approved. I am very happy because I personally like this image very much. Thanks DT!
Here is the image: