[BUG] Crash when preview window open and settings window closing (v2.1.0)

[jojje]

To reproduce:

1. Ensure: Settings > UI > Image preview location = Separate window
2. File > Load Folder
3. Select an image and open the preview window (CTRL+P)
4. Open Settings > Settings... and click Cancel or Save.

Instant crash

************** Exception Text **************
System.ArgumentException: Parameter is not valid.
   at System.Drawing.Image.get_Width()
   at System.Drawing.Image.get_Size()
   at System.Windows.Forms.PictureBox.ImageRectangleFromSizeMode(PictureBoxSizeMode mode)
   at System.Windows.Forms.PictureBox.OnPaint(PaintEventArgs pe)
   at System.Windows.Forms.Control.PaintWithErrorHandling(PaintEventArgs e, Int16 layer)
   at System.Windows.Forms.Control.WmPaint(Message& m)
   at System.Windows.Forms.Control.WndProc(Message& m)
   at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
   at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, WM msg, IntPtr wparam, IntPtr lparam)

[starik222]

Fixed in 2.1.1