is that satoshi?

Who knows? If it is, it isn't canon. Last I recall, Satoshi was stinking up a plastic bag a few towns over, and that's from outside the time-loop, so its pretty definite.

Tenebrous said:
spoiler

That's wrong. The one in the plastic bag was Rina.
But since this is higurashi, the picture could as well be canon in one of the worlds

By Rina I assume you mean Rena? I don't remember that, but like you said, it's Higurashi, so there's no point for me to over analyze it. -_-

Tenebrous said:
By Rina I assume you mean Rena? I don't remember that, but like you said, it's Higurashi, so there's no point for me to over analyze it. -_-

I don't think so Rina was Satoshi/Satoko's uncle's mistress

There is more than one corpse in there, and since shion-mion looks younger it might be related to tone of the manga exclusive arcs (the one that got canelled) that or it is from the kataribanashi.

That is probably Shion in the picture. She tends to get a bit more bloody than Mion. I don't think Mion has even gone on a rampage. It was always Shion acting as Mion.

Now that I look at it closer, that looks like the outfit Shion had when she escaped the boarding school...