diff --git a/index.src.html b/index.src.html
index d97ebc41..c760287d 100644
--- a/index.src.html
+++ b/index.src.html
@@ -5747,7 +5747,7 @@
 --------------------------------------------------------
 <pre class='idl'>
 <xmp>
-typedef (BufferSource or ReadableStream) ImageBufferSource;
+typedef (AllowSharedBufferSource or ReadableStream) ImageBufferSource;
 dictionary ImageDecoderInit {
   required DOMString type;
   required ImageBufferSource data;