diff --git a/modules/libimg/gifcom/nsGIFDecoder.cpp b/modules/libimg/gifcom/nsGIFDecoder.cpp
index f5baa1afbd6a..791df32cb8e2 100644
--- a/modules/libimg/gifcom/nsGIFDecoder.cpp
+++ b/modules/libimg/gifcom/nsGIFDecoder.cpp
@@ -50,7 +50,7 @@ class GIFDecoder : public nsIImgDecoder
 {
 public:
   GIFDecoder(il_container* aContainer);
-  ~GIFDecoder();
+  virtual ~GIFDecoder();
  
   NS_DECL_ISUPPORTS
 
@@ -110,7 +110,7 @@ public:
   NS_DECL_ISUPPORTS
 
   nsGIFDecFactory(const nsCID &aClass);
-  ~nsGIFDecFactory();
+  virtual ~nsGIFDecFactory();
 
   NS_IMETHOD CreateInstance(nsISupports *aOuter,
                             REFNSIID aIID,
diff --git a/modules/libimg/jpgcom/nsJPGCallback.h b/modules/libimg/jpgcom/nsJPGCallback.h
index eaa51098dc46..abf9f705300c 100644
--- a/modules/libimg/jpgcom/nsJPGCallback.h
+++ b/modules/libimg/jpgcom/nsJPGCallback.h
@@ -47,7 +47,7 @@ public:
   il_container *SetContainer(il_container *ic) {mContainer=ic; return ic;};
 
   JPGCallbk(il_container *aContainer){mContainer=aContainer;};
-  ~JPGCallbk() {};	// XXX Pam needs to fix this
+  virtual ~JPGCallbk() {};	// XXX Pam needs to fix this
 
 private:
   il_container* mContainer;
diff --git a/modules/libimg/jpgcom/nsJPGDecoder.cpp b/modules/libimg/jpgcom/nsJPGDecoder.cpp
index d25103087417..43efc3a3d935 100644
--- a/modules/libimg/jpgcom/nsJPGDecoder.cpp
+++ b/modules/libimg/jpgcom/nsJPGDecoder.cpp
@@ -50,7 +50,7 @@ class JPGDecoder : public nsIImgDecoder
 {
 public:
   JPGDecoder(il_container* aContainer);
-  ~JPGDecoder();
+  virtual ~JPGDecoder();
  
   NS_DECL_ISUPPORTS
 
@@ -159,7 +159,7 @@ public:
   NS_DECL_ISUPPORTS
 
   nsJPGDecFactory(const nsCID &aClass);
-  ~nsJPGDecFactory();
+  virtual ~nsJPGDecFactory();
 
   NS_IMETHOD CreateInstance(nsISupports *aOuter,
                             REFNSIID aIID,
diff --git a/modules/libimg/pngcom/nsPNGCallback.h b/modules/libimg/pngcom/nsPNGCallback.h
index e95dbc4f2c31..5d2771b8e17f 100644
--- a/modules/libimg/pngcom/nsPNGCallback.h
+++ b/modules/libimg/pngcom/nsPNGCallback.h
@@ -47,7 +47,7 @@ public:
   il_container *SetContainer(il_container *ic) {mContainer=ic; return ic;};
 
   PNGCallbk(il_container *aContainer){mContainer=aContainer;};
-  ~PNGCallbk() {};	// XXX Pam needs to fix this
+  virtual ~PNGCallbk() {};	// XXX Pam needs to fix this
 
 private:
   il_container* mContainer;
diff --git a/modules/libimg/pngcom/nsPNGDecoder.cpp b/modules/libimg/pngcom/nsPNGDecoder.cpp
index 566595b11f4e..fa4741154c14 100644
--- a/modules/libimg/pngcom/nsPNGDecoder.cpp
+++ b/modules/libimg/pngcom/nsPNGDecoder.cpp
@@ -50,7 +50,7 @@ class PNGDecoder : public nsIImgDecoder
 {
 public:
   PNGDecoder(il_container* aContainer);
-  ~PNGDecoder();
+  virtual ~PNGDecoder();
  
   NS_DECL_ISUPPORTS
 
@@ -111,7 +111,7 @@ public:
   NS_DECL_ISUPPORTS
 
   nsPNGDecFactory(const nsCID &aClass);
-  ~nsPNGDecFactory();
+  virtual ~nsPNGDecFactory();
 
   NS_IMETHOD CreateInstance(nsISupports *aOuter,
                             REFNSIID aIID,