diff --git a/lcl/include/picture.inc b/lcl/include/picture.inc
index 5ca42c6187..4e1b500d8e 100644
--- a/lcl/include/picture.inc
+++ b/lcl/include/picture.inc
@@ -389,13 +389,13 @@ end;
 
 function TPicture.GetPNG: TPortableNetworkGraphic;
 begin
-  ForceType(TPixmap);
+  ForceType(TPortableNetworkGraphic);
   Result := TPortableNetworkGraphic(Graphic);
 end;
 
 function TPicture.GetPNM: TPortableAnyMapGraphic;
 begin
-  ForceType(TPixmap);
+  ForceType(TPortableAnyMapGraphic);
   Result := TPortableAnyMapGraphic(Graphic);
 end;