diff --git a/Imaging/vtkImageImport.cxx b/Imaging/vtkImageImport.cxx
index 27a029c..0d6faa7 100644
--- a/Imaging/vtkImageImport.cxx
+++ b/Imaging/vtkImageImport.cxx
@@ -209,6 +209,23 @@
 }
 
 //----------------------------------------------------------------------------
+int vtkImageImport::ComputePipelineMTime(
+  vtkInformation* request,
+  vtkInformationVector** inInfoVec,
+  vtkInformationVector* outInfoVec,
+  int requestFromOutputPort,
+  unsigned long* mtime )
+{
+  if (this->InvokePipelineModifiedCallbacks())
+    {
+    this->Modified();
+    }
+  // Superclass normally returns our MTime.
+  return Superclass::ComputePipelineMTime(request, inInfoVec, outInfoVec,
+        requestFromOutputPort, mtime);
+}
+
+//----------------------------------------------------------------------------
 int vtkImageImport::RequestInformation (
   vtkInformation * vtkNotUsed(request),
   vtkInformationVector ** vtkNotUsed( inputVector ),
diff --git a/Imaging/vtkImageImport.h b/Imaging/vtkImageImport.h
index 805862e..7d86597 100644
--- a/Imaging/vtkImageImport.h
+++ b/Imaging/vtkImageImport.h
@@ -116,6 +116,14 @@
   virtual int RequestUpdateExtent(  vtkInformation* request,
                                     vtkInformationVector** inputVector,
                                     vtkInformationVector* outputVector);
+  // Description:
+  // Override vtkAlgorithm
+  virtual int
+  ComputePipelineMTime(vtkInformation* request,
+                       vtkInformationVector** inInfoVec,
+                       vtkInformationVector* outInfoVec,
+                       int requestFromOutputPort,
+                       unsigned long* mtime);
 
   // Description:
   // Set/get the scalar array name for this data set. Initial value is