user page: fix bg image layout shift

assets/views/user.jet.html

@@ -19,7 +19,10 @@
       <div class="d-flex position-relative mb-5 mb-md-0">
         <img src="{{ .User.BackgroundImage }}" alt="{{ .User.Name }} profile background image"
              class="img-fluid rounded-top-5 object-fit-cover w-100"
-             style="max-height: 200px;" />
+             style="max-height: 200px;"
+             width="1920px"
+             height="960px"
+        />
         <img src="{{.User.Avatar}}" alt="User avatar"
              class="d-inline-block d-md-none border border-5 border-neutral-800 rounded-circle object-fit-cover position-absolute z-1"
              style="width: 150px; height: 150px; bottom: 0; left: 50%; transform: translate(-50%, 50%);">