Otto, you are willing to make the assumption that those inside shutters were open? Because that would support the possibility that the rock could have been thrown from outside (assuming that the person first climbed up to pull open the green shutters.) Whether anyone actually climbed in from there is another matter.
I wonder what the opposite glass looks like. Because if that mark on the shutter (beside the digital number 7 in the 2007 date) in your blown up picture is the rock hitting the window, would the other pane on the opposite side be broken?
The inside shutters had to be open to break the glass from the inside.
Filomina's window testimony per court conclusions:
"Filomena Romanelli stated (cf. declarations at the hearing of February 7, 2009) that when she left the house in via della Pergola 7 on the afternoon of November 1, 2007
she had closed the shutters of her window (p. 68); she had pulled them in (p. 95); "the wood was slightly swelled, so they rubbed against the windowsill" (p. 26), adding that "it was an old window...the wood rubbed". And on the day she went away, she recalled "having closed them because I knew that I would be away for a couple of days" (p. 96). She later added, when noting what she had declared on December 3, 2007, that "I had pulled the shutters together, but I don't think I closed them tight" (p. 115).
[36] It must be held that when Filomena Romanelli left the house in via della Pergola, she had pulled the shutters towards the interior of her room, although she did not think that she had actually closed them; furthermore, because they were old and the wood had swelled a bit, they rubbed on the windowsill; to pull them towards the room it was necessary to use some force ("they rubbed on the windowsill"); but in this way, once they had been pulled in, as Romanelli remembered doing, they remained well closed by the pressure of the swelled wood against the windowsill."
Ref: pg 48
It cannot be assumed - as the Defence Consultant did - that the shutters were left completely open, since this contradicts the declarations of Romanelli, which appear to be detailed and entirely likely, considering that she was actually leaving for the holiday and had some things of value in her room; already she did not feel quite safe because window-frames were in wood [38] without any grille. Also, the circumstance of the shutters being wide open does not correspond to their position when they were found and described by witnesses on November 2, and photographed (cf. photo 11 already mentioned)."
Ref: pg 50
"As for the presence of glass in Romanelli's room, the violence of the blow, the characteristics of the glass (which was rather thin as indicated by Romanelli and Pasquali), the large rock used, and finally the shield effect caused by
the inner shutter hanging half-open behind the glass pane [41] (a position of the inner shutter which corresponds to the scratch on it visible in the photos) give an adequate explanation of the distribution of the glass."
Ref: pg 52