diff --git a/src/fix.h b/src/fix.h
index bfbee2940fe40b87da041e32274979cf6dc0221c..9dfb642096d45d20d8f512a22aff38ae89a0c0d6 100644
--- a/src/fix.h
+++ b/src/fix.h
@@ -204,6 +204,8 @@ class Fix : protected Pointers {
 
   virtual void rebuild_special() {}
 
+  virtual int image(int *&, double **&) {return 0;}
+
   virtual int modify_param(int, char **) {return 0;}
   virtual void *extract(const char *, int &) {return NULL;}