diff --git a/doc/src/packages.tex b/doc/src/packages.tex
index 542a6a8b..c2a2c1e1 100644
--- a/doc/src/packages.tex
+++ b/doc/src/packages.tex
@@ -844,7 +844,8 @@ im_version_string  - VIPS version string
 See \fref{fg:format}.
 
 These functions convert to and from various image formats. See
-\pref{sec:format} for a nice API over these functions.
+\pref{sec:format} for a nice API over these. VIPS can read more than these
+formats, see the man page for \verb+VipsFormat+.
 
 \begin{fig2}
 \begin{verbatim}