diff --git a/scribblings/cs019.scrbl b/scribblings/cs019.scrbl
index c94adca..56445f7 100644
--- a/scribblings/cs019.scrbl
+++ b/scribblings/cs019.scrbl
@@ -932,6 +932,10 @@ may be useful when deploying a finished program.
 @section[#:tag "bugs"]{Known bugs and deviations}
 
 @itemize[
+
+@item{@racket[image-url] doesn't currently work with offline app
+support.  Use @racket[define-resource] instead.}
+
 @item{Whalesong's compiler doesn't know how to compile programs with
 embedded image snips.  You can work around this by using
 @racket[define-resource], and save an image file in the same directory