update image dimen in paintTo method

frontend/ui/widget/image.lua

@@ -29,6 +29,11 @@ end
 
 function ImageWidget:paintTo(bb, x, y)
 	local size = self:getSize()
+	self.dimen = Geom:new{
+		x = x, y = y,
+		w = size.w,
+		h = size.h 
+	}
 	bb:blitFrom(self._bb, x, y, 0, 0, size.w, size.h)
 	if self.invert then
 		bb:invertRect(x, y, size.w, size.h)