diff --git a/src/jpeg.cc b/src/jpeg.cc
index 4c64b16..2c8ef8a 100644
--- a/src/jpeg.cc
+++ b/src/jpeg.cc
@@ -422,8 +422,8 @@ static void Jpeg_write(DilloJpeg *jpeg, void *Buf, uint_t BufSize)
 
 #else /* ENABLE_JPEG */
 
-void *a_Jpeg_new() { return 0; }
-void a_Jpeg_callback() { return; }
+void *a_Jpeg_new(DilloImage *, DilloUrl *, int) { return 0; }
+void a_Jpeg_callback(int, void *) { return; }
 const char *a_Jpeg_version(void) { return 0; }
 
 #endif /* ENABLE_JPEG */