He's inadvertently thumbnailing self.img with PIL (to display it in the Tk widget). So when self.img.size is called later on, the new smaller thumbnail size is the one being returned.
Lots of different ways to tackle correcting it. A down-and-dirty-way to get it going would be to make a few similar changes in two different locations.
In plugin.py (latest version) starting with line #255 change:
Code:
self.img = Image.open(BytesIO(bkImage))
size = 400, 400
self.img.thumbnail(size, Image.ANTIALIAS)
self.photo = ImageTk.PhotoImage(self.img)
to:
Code:
img_temp = Image.open(BytesIO(bkImage))
self.img = img_temp.copy()
size = 400, 400
img_temp.thumbnail(size, Image.ANTIALIAS)
self.photo = ImageTk.PhotoImage(img_temp)
And in plugin.py line #275 (before the above change) change:
Code:
self.img = Image.open(filehandle.name)
size = 400, 400
self.img.thumbnail(size, Image.ANTIALIAS)
self.photo = ImageTk.PhotoImage(self.img)
to:
Code:
img_temp = Image.open(filehandle.name)
self.img = img_temp.copy()
size = 400, 400
img_temp.thumbnail(size, Image.ANTIALIAS)
self.photo = ImageTk.PhotoImage(img_temp)