diff --git a/.gitignore b/.gitignore
index 2440dea8..3efdaf44 100644
--- a/.gitignore
+++ b/.gitignore
@@ -4,6 +4,8 @@
 *egg-info
 *.so
 *.bak
+*.c
+.gitignore
 doc/source/api
 doc/build
 source/api
diff --git a/scikits/image/io/_plugins/gtk_plugin.py b/scikits/image/io/_plugins/gtk_plugin.py
index b6bfe1ca..d6619d3d 100644
--- a/scikits/image/io/_plugins/gtk_plugin.py
+++ b/scikits/image/io/_plugins/gtk_plugin.py
@@ -40,10 +40,14 @@ else:
         iw = ImageWindow(arr, window_manager)
         iw.show()
 
-    def show():
-        window_manager.register_callback(gtk.main_quit)
-        gtk.main()
+    def gtk_show():
+        if window_manager.has_images():
+            window_manager.register_callback(gtk.main_quit)
+            gtk.main()
+        else:
+            print 'no images to display'
+
+
+    plugin.register('gtk', show=gtk_imshow, appshow=gtk_show)
 
-    plugin.register('gtk', show=gtk_imshow)
-    plugin.register('gtk', appshow=show)
 
diff --git a/scikits/image/io/_plugins/util.py b/scikits/image/io/_plugins/util.py
index 24c765f9..f6e9e921 100644
--- a/scikits/image/io/_plugins/util.py
+++ b/scikits/image/io/_plugins/util.py
@@ -11,7 +11,6 @@ class WindowManager(object):
         self._callback = None
         self._callback_args = ()
         self._callback_kwargs = {}
-
         self._gui_lock = False
 
     def _check_locked(self):
@@ -19,8 +18,11 @@ class WindowManager(object):
             raise RuntimeError(\
             'Must first acquire the gui lock before using this image manager ')
 
+    def _exec_callback(self):
+        if self._callback:
+            self._callback(*self._callback_args, **self._callback_kwargs)
+
     def acquire(self):
-        print 'lock requested while: ', self._gui_lock
         if self._gui_lock:
             raise RuntimeError(\
             'The gui lock can only be acquired by one toolkit per session')
@@ -28,32 +30,35 @@ class WindowManager(object):
             self._gui_lock = True
 
     def add_window(self, win):
+        self._check_locked()
         self._windows.append(win)
 
     def remove_window(self, win):
+        self._check_locked()
         try:
             self._windows.remove(win)
         except ValueError:
             print 'Unable to find referenced window in tracked windows.'
             print 'Ignoring...'
         else:
-            print len(self._windows)
-            if len(self._windows)==0:
+            if len(self._windows) == 0:
                 self._exec_callback()
 
     def register_callback(self, cb, *cbargs, **cbkwargs):
+        self._check_locked()
         self._callback = cb
-        print self._callback
         self._callback_args = cbargs
         self._callback_kwargs = cbkwargs
 
-    def _exec_callback(self):
-        if self._callback:
-            print 'calling callback'
-            self._callback(*self._callback_args, **self._callback_kwargs)
+    def has_images(self):
+        if len(self._windows) > 0:
+            return True
+        else:
+            return False
 
 window_manager = WindowManager()
 
+
 def prepare_for_display(npy_img):
     '''Convert a 2D or 3D numpy array of any dtype into a
     3D numpy array with dtype uint8. This array will
diff --git a/scikits/image/io/io.py b/scikits/image/io/io.py
index 60f340c2..aaf826a4 100644
--- a/scikits/image/io/io.py
+++ b/scikits/image/io/io.py
@@ -90,5 +90,14 @@ def imshow(arr, plugin=None, **plugin_args):
     return call_plugin('show', arr, plugin=plugin, **plugin_args)
 
 def show():
-    # need some checks here, now just for testing
+    '''Launches the event loop of the current gui plugin,
+    and displays all pending images. This is required,
+    when using imshow() from a non-interactive script.
+    Simply make all the calls to imshow() to queue up as many
+    images as you need, then call show(). After the
+    last window is closed, the gui event loop will exit,
+    and you script will continue execution.
+
+    If this is called from the interactive terminal,
+    it will block until all windows are closed.'''
     return call_plugin('appshow')