ensure the avatar path

src/Yavsc.Org/Views/Manage/SetAvatar.cshtml

@@ -1,9 +1,14 @@
-@model PerformerProfile 
-@{ ViewBag.Title = "Edit your avatar"; } 
+@model PerformerProfile
+@{ ViewBag.Title = "Edit your avatar"; }
+@{
+    var previewAvatarSrc = string.IsNullOrWhiteSpace(User?.Identity?.Name)
+        ? Yavsc.Constants.DefaultAvatar
+        : $"{Yavsc.Constants.AvatarsPath}/{User.Identity.Name}.png";
+}
 @section header{
 <script src="https://unpkg.com/dropzone@5/dist/min/dropzone.min.js"></script>
 <link rel="stylesheet" href="https://unpkg.com/dropzone@5/dist/min/dropzone.min.css" type="text/css" />
-} 
+}
 @section scripts{
 <script>
 $(document).ready(function() {
@@ -21,7 +26,7 @@ $(document).ready(function() {
   });
 </script>
 }
-<img src="~/avatars/@(User.Identity.Name).png">
+<img src="@previewAvatarSrc">
 
 <form id="postavatar" action="/api/setavatar" class="dropzone" method="post" enctype="multipart/form-data">
     <div class="fallback">