diff --git a/.gitignore b/.gitignore
index 1fb97daa..d43dbf65 100644
--- a/.gitignore
+++ b/.gitignore
@@ -15,7 +15,7 @@ vendor/
 /plugins/
 
 # The theme is probably managed in its own repo.
-themes/
+/themes/
 
 # Uploads are... uploads.
 uploads/
diff --git a/mu-plugins/index.php b/mu-plugins/index.php
index 0795553a..f267c783 100644
--- a/mu-plugins/index.php
+++ b/mu-plugins/index.php
@@ -12,6 +12,8 @@
 require_once __DIR__ . '/plugins/indieweb.php';
 require_once __DIR__ . '/plugins/micropub.php';
 
+require_once __DIR__ . '/themes/writemore.php';
+
 if ( file_exists( __DIR__ . '/local/hacks.php' ) ) {
 	require_once __DIR__ . '/local/hacks.php';
 }
diff --git a/mu-plugins/themes/writemore.php b/mu-plugins/themes/writemore.php
new file mode 100644
index 00000000..fcdcbef3
--- /dev/null
+++ b/mu-plugins/themes/writemore.php
@@ -0,0 +1,19 @@
+<?php
+/**
+ * Customizations of the writemore theme.
+ *
+ * @package jeremyfelt
+ */
+
+namespace JeremyFelt\Writemore;
+
+add_filter( 'writemore_author_avatar_alt_text', __NAMESPACE__ . '\filter_author_avatar_alt_text' );
+
+/**
+ * Filter the alt text for the author avatar.
+ *
+ * @return string Modified alt text.
+ */
+function filter_author_avatar_alt_text(): string {
+	return "Jeremy's profile photo: a selfie taken while walking through Berlin.";
+}