diff --git a/cmd/app/kodata/index.html b/cmd/app/kodata/index.html
index d3c49a5..3f40970 100644
--- a/cmd/app/kodata/index.html
+++ b/cmd/app/kodata/index.html
@@ -32,6 +32,8 @@ container image using <a
 build and (eventually) serve a Docker image containing <code>ko</code> itself.
 <i>Koception!</i></p>
 
+<p><b>NB:</b> All Docker image references must be lowercase.</p>
+
 <h1><code>buildpack.kontain.me</code></h1>
 
 <p><code>docker pull buildpack.kontain.me/[ghuser]/[ghrepo]/[path/to/app]:[revision]</code>
@@ -41,20 +43,21 @@ serves an image fetched from source on GitHub and built using <a
  builder</a></p>
 
 <p>For example, <code>docker pull
-	buildpack.kontain.me/GoogleCloudPlatform/buildpack-samples/sample-go:master</code>
+	buildpack.kontain.me/googlecloudplatform/buildpack-samples/sample-go:master</code>
  fetches, builds and serves a <a
  href="https://github.com/GoogleCloudPlatform/buildpack-samples/tree/master/sample-go">sample
  Go app</a>.</p>
 
-The image tag can be a commit, branch or tag. The default,
-<code>:latest</code>, pulls the master branch.
+<p><b>NB:</b> All Docker image references must be lowercase.</p>
+
+<p>The image tag can be a commit, branch or tag. The default,
+<code>:latest</code>, pulls the master branch.</p>
 
 <h1>Caveats</h1>
 
-<p>The registry does not accept pushes and does not handle requests for images
-by digest. This is a silly hack and probably isn't stable. Don't rely on it for
-anything serious. It could probably do a lot of smart things to be a lot
-faster.</p>
+<p>The registry does not accept pushes of any kind. This is a silly hack and if
+it's at all reliable it's by accident. Don't rely on it for anything serious.
+It could probably do a lot of smart things to be a lot faster.</p>
 
 <p>Source is available on
 <a href="https://github.com/imjasonh/kontain.me">GitHub</a>.</p>
diff --git a/go.sum b/go.sum
index db04e1e..6011220 100644
--- a/go.sum
+++ b/go.sum
@@ -455,6 +455,7 @@ golang.org/x/sys v0.0.0-20200302150141-5c8b2ff67527/go.mod h1:h1NjWce9XRLGQEsW7w
 golang.org/x/sys v0.0.0-20200323222414-85ca7c5b95cd/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20200331124033-c3d80250170d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20200501052902-10377860bb8e/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20200511232937-7e40ca221e25 h1:OKbAoGs4fGM5cPLlVQLZGYkFC8OnOfgo6tt0Smf9XhM=
 golang.org/x/sys v0.0.0-20200511232937-7e40ca221e25/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/text v0.0.0-20160726164857-2910a502d2bf/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 golang.org/x/text v0.0.0-20170915032832-14c0d48ead0c/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=