diff --git a/lib/private/Avatar/GuestAvatar.php b/lib/private/Avatar/GuestAvatar.php
index e0eefa47b6b884c0dcec0bf77963cf6ab0b6fb9a..2a165d0ce7ce35210042e98137cb301da45f9768 100644
--- a/lib/private/Avatar/GuestAvatar.php
+++ b/lib/private/Avatar/GuestAvatar.php
@@ -90,8 +90,8 @@ class GuestAvatar extends Avatar {
 	 * @return InMemoryFile
 	 */
 	public function getFile($size) {
-		$avatar = $this->getAvatarVector($size);
-		return new InMemoryFile('avatar.svg', $avatar);
+		$avatar = $this->generateAvatar($this->userDisplayName, $size);
+		return new InMemoryFile('avatar.png', $avatar);
 	}
 
 	/**
diff --git a/tests/data/guest_avatar_einstein_32.png b/tests/data/guest_avatar_einstein_32.png
new file mode 100644
index 0000000000000000000000000000000000000000..58562b7d711333f963c6c187922a3c6e0722e712
Binary files /dev/null and b/tests/data/guest_avatar_einstein_32.png differ
diff --git a/tests/lib/Avatar/GuestAvatarTest.php b/tests/lib/Avatar/GuestAvatarTest.php
index 8762d063f5d7ef4d264903d8aa8e8d64b672339e..0d13655133b3e81811e3817b46e71f9445069da3 100644
--- a/tests/lib/Avatar/GuestAvatarTest.php
+++ b/tests/lib/Avatar/GuestAvatarTest.php
@@ -64,7 +64,7 @@ class GuestAvatarTest extends TestCase {
 		$avatar = $this->guestAvatar->getFile(32);
 		self::assertInstanceOf(InMemoryFile::class, $avatar);
 		$expectedFile = file_get_contents(
-			__DIR__ . '/../../data/guest_avatar_einstein_32.svg'
+			__DIR__ . '/../../data/guest_avatar_einstein_32.png'
 		);
 		self::assertEquals(trim($expectedFile), trim($avatar->getContent()));
 	}