Fix profile banner url

app/src/components/profile-header/profile-header.ts

@@ -19,7 +19,7 @@ export class ProfileHeaderComponent {
 
   get banner() {
     if (this.user.profile_banner_url) {
-      return this.user.profile_banner_url;
+      return this.user.profile_banner_url + "/1500x500";
     } else {
       return this.user.profile_background_image_url_https;
     }