Alleged spoiler from S2E4
It's wooonaaaaa
Not Luna. Here's a side by side of the mystery pony with Luna from S1E2:
The coat, mane, horn, and eyes are all different colors. It's possible the mystery pony might be Luna colored differently to indicate that it's night time, but if so it's peculiar that while the body of the mane is darker, the outline of the mane is lighter. Also, while I haven't compared lots of pony pics up close to see how consistent the artwork is, I also notice that the direction of the gradient in the iris are vertically inverted between the two pictures, the eyelashes are very different, and the nostrils are angled differently.
Probably not Luna.
EDIT: Watched a clip up close. The source animation is wildly inconsistent about eyebrows and eyelashes. There are places where over 5 seconds a pony may go back and forth a couple times between even having or not having eyebrows and lower eyelashes, and the shape and placement varies almost from word to word. So, different eyelashes doesn't mean much. But still, looking at the images side by side, that doesn't look like Luna to me.
Who's good at recognizing shops by their pixels and seeing lots of shops in their time?
Two out of three of the
images in question are photographs of computer screens, and the third is from a storyboard. It would be difficult to determine if the originals were photoshopped.
However, it's noteworthy that the text on the storyboard image refers to Derpy as "Derpy" and not "Ditzy Doo."