diff --git a/changelog.d/12510.bugfix b/changelog.d/12510.bugfix
new file mode 100644
index 000000000..d5856e982
--- /dev/null
+++ b/changelog.d/12510.bugfix
@@ -0,0 +1 @@
+Fix a long-standing bug where the image thumbanils embedded into email notifications were broken.
diff --git a/synapse/res/templates/notif.html b/synapse/res/templates/notif.html
index 0aaef97df..7d86681fe 100644
--- a/synapse/res/templates/notif.html
+++ b/synapse/res/templates/notif.html
@@ -30,7 +30,7 @@
                     {%- elif message.msgtype == "m.notice" %}
                         {{ message.body_text_html }}
                     {%- elif message.msgtype == "m.image" and message.image_url %}
-                        <img src="{{ message.image_url|mxc_to_http(640, 480, scale) }}" />
+                        <img src="{{ message.image_url|mxc_to_http(640, 480, 'scale') }}" />
                     {%- elif message.msgtype == "m.file" %}
                         <span class="filename">{{ message.body_text_plain }}</span>
                     {%- else %}