Internetowa łamigłówka «Sailboat»

the picture is gorgeous, but not sure as the sky with a strange texture, as if the projector was sent to the Wallpaper off the wall, and the pattern of the Wallpaper was in the frame too, although this is even something
gulls wings of the strokes and the strange yellow ghosting, or is this normal? some of the hdr format?
in General I wonder, what do the experts say, I'll abstain from voting