Comment 4 for bug 290654

All I can do at the moment is reproduce the following.

Make a selection (Like star rating 1 *)
Make sure that there is only one photo.

Then Open that photo in large (not thumbnail) mode
The right click and delete....

It dumps:
[Info 11:05:25.855] BaseDirectory is now /media/data/mydocs/pics/fspotdbs/all
[Info 11:05:25.864] Initializing DBus
[Info 11:05:26.094] Initializing Mono.Addins
[Info 11:05:27.085] Starting new FSpot server
get fences failed: -1
param: 6, val: 0
[Info 11:05:29.493] Starting DBusService
[Info 11:05:29.505] Starting BeagleService
[Info 11:05:29.506] Hack for gnome-settings-daemon engaged

(f-spot:14540): GdkPixbuf-WARNING **: GdkPixbufLoader finalized without calling gdk_pixbuf_loader_close() - this is not allowed. You must explicitly end the data stream to the loader before dropping the last reference.
Syncing metadata to file...
old = "" new = "" heading = "ASCII"
value = 2009:04:26 16:03:34 len = 19
_:bnode506143744 <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://www.w3.org/1999/02/22-rdf-syntax-ns#Bag> .
_:bnode506143744 <http://www.w3.org/1999/02/22-rdf-syntax-ns#li> "SunSets" .
<http://fakebase.f-spot.org/internal/> <http://purl.org/dc/elements/1.1/subject> _:bnode506143744 .
<http://fakebase.f-spot.org/internal/> <http://ns.adobe.com/xap/1.0/Rating> "1" .
value = f-spot version 0.5.0.3 len = 22
value = 2009:05:03 11:05:59 len = 19
value = f-spot version 0.5.0.3 len = 22
value = 2009:05:03 11:06:00 len = 19
Saved 11900 bytes
Exception in Gtk# callback delegate
  Note: Applications can use GLib.ExceptionManager.UnhandledException to handle the exception.
System.ArgumentNullException: Argument cannot be null.
Parameter name: key
  at System.Collections.Generic.Dictionary`2[System.Object,System.Object].set_Item (System.Object key, System.Object value) [0x00000]
  at FSpot.Utils.DisposableCache`2[System.String,Gdk.Pixbuf].Add (System.String key, Gdk.Pixbuf value) [0x00000]
  at FSpot.Widgets.Filmstrip.GetPixbuf (Int32 i, Boolean highlighted) [0x00000]
  at FSpot.Widgets.Filmstrip.GetPixbuf (Int32 i) [0x00000]
  at FSpot.Widgets.Filmstrip.OnExposeEvent (Gdk.EventExpose evnt) [0x00000]
  at Gtk.Widget.exposeevent_cb (IntPtr widget, IntPtr evnt) [0x00000]
   at GLib.ExceptionManager.RaiseUnhandledException(System.Exception e, Boolean is_terminal)
   at Gtk.Widget.exposeevent_cb(IntPtr widget, IntPtr evnt)
   at Gtk.Application.gtk_main()
   at Gtk.Application.Run()
   at Gnome.Program.Run()
   at FSpot.Driver.Main(System.String[] args)

Hope this helps.