diff --git a/synapse/rest/media/v1/identicon_resource.py b/synapse/rest/media/v1/identicon_resource.py
index 636e3a33c2..12d98e1774 100644
--- a/synapse/rest/media/v1/identicon_resource.py
+++ b/synapse/rest/media/v1/identicon_resource.py
@@ -41,8 +41,8 @@ class IdenticonResource(Resource):
 
     def render_GET(self, request):
         name = "/".join(request.postpath)
-        width = int(request.args.get("width", 96))
-        height = int(request.args.get("height", 96))
+        width = int(request.args.get("width", [96])[0])
+        height = int(request.args.get("height", [96])[0])
         identicon_bytes = self.generate_identicon(name, width, height)
         request.setHeader(b"Content-Type", b"image/png")
         return identicon_bytes