diff --git a/src/osx/core/bitmap.cpp b/src/osx/core/bitmap.cpp
index bb8b8da564..550fc9c6d1 100644
--- a/src/osx/core/bitmap.cpp
+++ b/src/osx/core/bitmap.cpp
@@ -324,14 +324,14 @@ int wxBitmapRefData::GetDepth() const
     else
         return 32; // a bitmap converted from an nsimage would have this depth
 }
+
 int wxBitmapRefData::GetBytesPerRow() const
 {
     wxCHECK_MSG( IsOk() , 0 , "Invalid Bitmap");
 
-    if ( m_hBitmap )
-        return (int) CGBitmapContextGetBytesPerRow(m_hBitmap);
-    else
-        return (int) GetBestBytesPerRow( GetWidth() * 4);
+    // Row stride length makes sense only for a bitmap representation
+    EnsureBitmapExists();
+    return (int) CGBitmapContextGetBytesPerRow(m_hBitmap);
 }
 
 bool wxBitmapRefData::HasAlpha() const