```diff
diff --git a/pkgs/development/libraries/libavif/default.nix b/pkgs/development/libraries/libavif/default.nix
index 46153ce516c..817b65576f7 100644
--- a/pkgs/development/libraries/libavif/default.nix
+++ b/pkgs/development/libraries/libavif/default.nix
@@ -23,7 +23,7 @@ stdenv.mkDerivation rec {
 
   # reco: encode libaom slowest but best, decode dav1d fastest
 
-  PKG_CONFIG_GDK_PIXBUF_2_0_GDK_PIXBUF_MODULEDIR = "${placeholder "out"}/${gdk-pixbuf.moduleDir}";
+  PKG_CONFIG_GDK_PIXBUF_2_0_GDK_PIXBUF_MODULEDIR = "${placeholder "loader"}/${gdk-pixbuf.moduleDir}";
 
   cmakeFlags = [
     "-DBUILD_SHARED_LIBS=ON"
@@ -48,10 +48,12 @@ stdenv.mkDerivation rec {
   ];
 
   postInstall = ''
-    mkdir -p $out/share/thumbnailers
-    cat ${./thumbnailer} | sed "s|@bindir@|${gdk-pixbuf}/bin|g" > $out/share/thumbnailers/libavif.thumbnailer
+    mkdir -p $loader/share/thumbnailers
+    cat ${./thumbnailer} | sed "s|@bindir@|${gdk-pixbuf}/bin|g" > $loader/share/thumbnailers/libavif.thumbnailer
   '';
 
+  outputs = [ "out" "loader" ];
+
   meta = with stdenv.lib; {
     description  = "C implementation of the AV1 Image File Format";
     longDescription = ''

```