diff --git a/include/freetype/ftimage.h b/include/freetype/ftimage.h
index 9d7f6b77d..7d4a99f38 100644
--- a/include/freetype/ftimage.h
+++ b/include/freetype/ftimage.h
@@ -21,6 +21,10 @@
    * Note: A 'raster' is simply a scan-line converter, used to render
    *       `FT_Outline`s into `FT_Bitmap`s.
    *
+   * Note: This file can be used for STANDALONE_ compilation of raster (B/W)
+   *       and smooth (anti-aliased) renderers.  Therefore, it must rely on
+   *       standard variable types only rather than aliases in fttypes.h.
+   *
    */