--- a/libinterp/corefcn/graphics.in.h	Fri Jul 04 21:40:50 2014 -0700
+++ b/libinterp/corefcn/graphics.in.h	Mon Apr 14 22:53:44 2014 +0200
@@ -4504,8 +4504,8 @@
       radio_property cdatamapping al , "scaled|{direct}"
       string_property displayname , ""
       radio_property erasemode , "{normal}|none|xor|background"
-      row_vector_property xdata u , Matrix ()
-      row_vector_property ydata u , Matrix ()
+      row_vector_property xdata mu , Matrix ()
+      row_vector_property ydata mu , Matrix ()
       // hidden properties for limit computation
       row_vector_property alim hlr , Matrix ()
       row_vector_property clim hlr , Matrix ()
@@ -4515,6 +4515,8 @@
       bool_property climinclude hlg , "on"
       bool_property xliminclude hl , "on"
       bool_property yliminclude hl , "on"
+      radio_property xdatamode ha , "{auto}|manual"
+      radio_property ydatamode ha , "{auto}|manual"
     END_PROPERTIES
 
   protected:
@@ -4551,10 +4553,25 @@
         set_clim (cdata.get_limits ());
       else
         clim = cdata.get_limits ();
+
+      if (xdatamode.is ("auto"))
+        update_xdata ();
+      
+      if (ydatamode.is ("auto"))
+        update_ydata ();
     }
 
     void update_xdata (void)
     {
+      if (xdata.get ().is_empty ())
+        set_xdatamode ("auto");
+        
+      if (xdatamode.is ("auto"))
+        {
+          set_xdata (get_auto_xdata ());
+          set_xdatamode ("auto");
+        }
+      
       Matrix limits = xdata.get_limits ();
       float dp = pixel_xsize ();
 
@@ -4565,6 +4582,15 @@
 
     void update_ydata (void)
     {
+      if (ydata.get ().is_empty ())
+        set_ydatamode ("auto");
+        
+      if (ydatamode.is ("auto"))
+        {
+          set_ydata (get_auto_ydata ()); 
+          set_ydatamode ("auto");
+        }
+      
       Matrix limits = ydata.get_limits ();
       float dp = pixel_ysize ();
 
@@ -4573,6 +4599,30 @@
       set_ylim (limits);
     }
 
+    Matrix get_auto_xdata (void)
+    {
+      dim_vector dv = get_cdata ().dims ();
+      Matrix data;
+      if (dv(1) > 0.)
+        {
+          data = Matrix (1, 2, 1);
+          data(1) = dv(1);
+        }
+      return data;
+    }
+
+    Matrix get_auto_ydata (void)
+    {
+      dim_vector dv = get_cdata ().dims ();
+      Matrix data;
+      if (dv(0) > 0.)
+        {
+          data = Matrix (1, 2, 1);
+          data(1) = dv(0);
+        }
+      return data;
+    }
+
     float pixel_size (octave_idx_type dim, const Matrix limits)
     {
       octave_idx_type l = dim - 1;

--- a/scripts/image/image.m	Fri Jul 04 21:40:50 2014 -0700
+++ b/scripts/image/image.m	Mon Apr 14 22:53:44 2014 +0200
@@ -144,16 +144,17 @@
   if (! isempty (img))
 
     if (isempty (x))
-      x = [1, columns(img)];
+      xdata = [];
+    else
+      xdata = x([1, end])(:).';  # (:).' is a hack to guarantee row vector
     endif
 
     if (isempty (y))
-      y = [1, rows(img)];
+      ydata = [];
+    else
+      ydata = y([1, end])(:).';
     endif
 
-    xdata = x([1, end])(:).';  # (:).' is a hack to guarantee row vector
-    ydata = y([1, end])(:).';
-
     if (numel (x) > 2 && numel (y) > 2)
       ## Test data for non-linear spacing which is unsupported
       tol = .01;  # 1% tolerance.  FIXME: this value was chosen without thought.
@@ -220,4 +221,31 @@
 %!  h = image (-x, -y, img);
 %!  title ("image (-x, -y, img)");
 
+%!test
+%! ## test hidden properties x/ydatamode (bug #42121)
+%! hf = figure ("visible", "off");
+%! unwind_protect
+%!   nx = 64; ny = 64;
+%!   cdata = rand (ny, nx)*127;
+%!   hi = image (cdata);             # x/ydatamode is auto
+%!   assert (get (hi, "xdata"), [1 nx])
+%!   assert (get (hi, "ydata"), [1 ny])
+%!   set (hi, "cdata", cdata(1:2:end, 1:2:end))
+%!   assert (get (hi, "xdata"), [1 nx/2])
+%!   assert (get (hi, "ydata"), [1 ny/2])
+%! 
+%!   set (hi, "xdata", [10 100])     # xdatamode is now manual
+%!   set (hi, "ydata", [10 1000])    # ydatamode is now manual
+%!   set (hi, "cdata", cdata)
+%!   assert (get (hi, "xdata"), [10 100])
+%!   assert (get (hi, "ydata"), [10 1000])
+%! 
+%!   set (hi, "ydata", [])           # ydatamode is now auto
+%!   set (hi, "cdata", cdata(1:2:end, 1:2:end))
+%!   assert (get (hi, "xdata"), [10 100])
+%!   assert (get (hi, "ydata"), [1 ny/2])
+%! unwind_protect_cleanup
+%!   close (hf)
+%! end_unwind_protect
+
 ## FIXME: Need %!tests for linear