diff --git a/scripts/make_identicons.pl b/scripts/make_identicons.pl
new file mode 100755
index 000000000..cbff63e29
--- /dev/null
+++ b/scripts/make_identicons.pl
@@ -0,0 +1,39 @@
+#!/usr/bin/env perl
+
+use strict;
+use warnings;
+
+use DBI;
+use DBD::SQLite;
+use JSON;
+use Getopt::Long;
+
+my $db; # = "homeserver.db";
+my $server = "http://localhost:8008";
+my $size = 320;
+
+GetOptions("db|d=s",     \$db,
+           "server|s=s", \$server,
+           "width|w=i",  \$size) or usage();
+
+usage() unless $db;
+
+my $dbh = DBI->connect("dbi:SQLite:dbname=$db","","") || die $DBI::errstr;
+
+my $res = $dbh->selectall_arrayref("select token, name from access_tokens, users where access_tokens.user_id = users.id group by user_id") || die $DBI::errstr;
+
+foreach (@$res) {
+    my ($token, $mxid) = ($_->[0], $_->[1]);
+    my ($user_id) = ($mxid =~ m/@(.*):/);
+    my ($url) = $dbh->selectrow_array("select avatar_url from profiles where user_id=?", undef, $user_id);
+    if (!$url || $url =~ /#auto$/) {
+        `curl -s -o tmp.png "$server/_matrix/media/v1/identicon?name=${mxid}&width=$size&height=$size"`;
+        my $json = `curl -s -X POST -H "Content-Type: image/png" -T "tmp.png" $server/_matrix/media/v1/upload?access_token=$token`;
+        my $content_uri = from_json($json)->{content_uri};
+        `curl -X PUT -H "Content-Type: application/json" --data '{ "avatar_url": "${content_uri}#auto"}' $server/_matrix/client/api/v1/profile/${mxid}/avatar_url?access_token=$token`;
+    }
+}
+
+sub usage {
+    die "usage: ./make-identicons.pl\n\t-d database [e.g. homeserver.db]\n\t-s homeserver (default: http://localhost:8008)\n\t-w identicon size in pixels (default 320)";
+}
\ No newline at end of file
diff --git a/synapse/handlers/register.py b/synapse/handlers/register.py
index 66a89c10b..4f06c487b 100644
--- a/synapse/handlers/register.py
+++ b/synapse/handlers/register.py
@@ -99,6 +99,23 @@ class RegistrationHandler(BaseHandler):
                         raise RegistrationError(
                             500, "Cannot generate user ID.")
 
+        # create a default avatar for the user
+        # XXX: ideally clients would explicitly specify one, but given they don't
+        # and we want consistent and pretty identicons for random users, we'll
+        # do it here.
+        try:
+            auth_user = UserID.from_string(user_id)
+            identicon_resource = self.hs.get_resource_for_media_repository().getChildWithDefault("identicon", None)
+            upload_resource = self.hs.get_resource_for_media_repository().getChildWithDefault("upload", None)
+            identicon_bytes = identicon_resource.generate_identicon(user_id, 320, 320)
+            content_uri = yield upload_resource.create_content(
+                "image/png", None, identicon_bytes, len(identicon_bytes), auth_user
+            )
+            profile_handler = self.hs.get_handlers().profile_handler
+            profile_handler.set_avatar_url(auth_user, auth_user, ("%s#auto" % content_uri))
+        except NotImplementedError:
+            pass # make tests pass without messing around creating default avatars
+        
         defer.returnValue((user_id, token))
 
     @defer.inlineCallbacks
diff --git a/synapse/rest/media/v1/upload_resource.py b/synapse/rest/media/v1/upload_resource.py
index b939a30e1..5b4278233 100644
--- a/synapse/rest/media/v1/upload_resource.py
+++ b/synapse/rest/media/v1/upload_resource.py
@@ -38,6 +38,35 @@ class UploadResource(BaseMediaResource):
     def render_OPTIONS(self, request):
         respond_with_json(request, 200, {}, send_cors=True)
         return NOT_DONE_YET
+        
+    @defer.inlineCallbacks
+    def create_content(self, media_type, upload_name, content, content_length, auth_user):
+        media_id = random_string(24)
+
+        fname = self.filepaths.local_media_filepath(media_id)
+        self._makedirs(fname)
+
+        # This shouldn't block for very long because the content will have
+        # already been uploaded at this point.
+        with open(fname, "wb") as f:
+            f.write(content)
+
+        yield self.store.store_local_media(
+            media_id=media_id,
+            media_type=media_type,
+            time_now_ms=self.clock.time_msec(),
+            upload_name=upload_name,
+            media_length=content_length,
+            user_id=auth_user,
+        )
+        media_info = {
+            "media_type": media_type,
+            "media_length": content_length,
+        }
+
+        yield self._generate_local_thumbnails(media_id, media_info)
+        
+        defer.returnValue("mxc://%s/%s" % (self.server_name, media_id))
 
     @defer.inlineCallbacks
     def _async_render_POST(self, request):
@@ -70,32 +99,10 @@ class UploadResource(BaseMediaResource):
             #    disposition = headers.getRawHeaders("Content-Disposition")[0]
             # TODO(markjh): parse content-dispostion
 
-            media_id = random_string(24)
-
-            fname = self.filepaths.local_media_filepath(media_id)
-            self._makedirs(fname)
-
-            # This shouldn't block for very long because the content will have
-            # already been uploaded at this point.
-            with open(fname, "wb") as f:
-                f.write(request.content.read())
-
-            yield self.store.store_local_media(
-                media_id=media_id,
-                media_type=media_type,
-                time_now_ms=self.clock.time_msec(),
-                upload_name=None,
-                media_length=content_length,
-                user_id=auth_user,
+            content_uri = yield self.create_content(
+                media_type, None, request.content.read(),
+                content_length, auth_user
             )
-            media_info = {
-                "media_type": media_type,
-                "media_length": content_length,
-            }
-
-            yield self._generate_local_thumbnails(media_id, media_info)
-
-            content_uri = "mxc://%s/%s" % (self.server_name, media_id)
 
             respond_with_json(
                 request, 200, {"content_uri": content_uri}, send_cors=True