diff --git a/web/app/controllers/problem_solutions.php b/web/app/controllers/problem_solutions.php
index 27fc649..6ace983 100644
--- a/web/app/controllers/problem_solutions.php
+++ b/web/app/controllers/problem_solutions.php
@@ -170,7 +170,7 @@ $pag = new Paginator($pag_config);
 						<div class="mb-3">
 							<span class="me-2 d-inline-block">
 								<a class="text-decoration-none" href="<?= HTML::url('/user/' . $poster['username']) ?>">
-									<img src="<?= HTML::avatar_addr($poster, 64) ?>" width="32" height="32" class="rounded" />
+									<img src="<?= HTML::avatar_addr($poster, 64) ?>" width="32" height="32" class="rounded uoj-user-avatar" />
 								</a>
 								<?= UOJUser::getLink($poster) ?>
 							</span>
diff --git a/web/app/controllers/subdomain/blog/blog.php b/web/app/controllers/subdomain/blog/blog.php
index 0cd54c6..215f90a 100644
--- a/web/app/controllers/subdomain/blog/blog.php
+++ b/web/app/controllers/subdomain/blog/blog.php
@@ -263,7 +263,7 @@ $comments_pag = new Paginator([
 				<div class="d-flex">
 					<div class="mr-3 flex-shrink-0">
 						<a href="<?= HTML::url('/user/' . $poster['username']) ?>" class="d-none d-sm-block text-decoration-none">
-							<img class="rounded" src="<?= $asrc ?>" alt="Avatar of <?= $poster['username'] ?>" width="64" height="64" />
+							<img class="rounded uoj-user-avatar" src="<?= $asrc ?>" alt="Avatar of <?= $poster['username'] ?>" width="64" height="64" />
 						</a>
 					</div>
 					<div id="comment-body-<?= $comment['id'] ?>" class="flex-grow-1 ms-3">
diff --git a/web/app/controllers/subdomain/blog/index.php b/web/app/controllers/subdomain/blog/index.php
index a711901..22184d3 100644
--- a/web/app/controllers/subdomain/blog/index.php
+++ b/web/app/controllers/subdomain/blog/index.php
@@ -32,7 +32,7 @@ $all_tags = DB::selectAll("select distinct tag from blogs_tags where blog_id in
 		<?= $blogs_pag->pagination() ?>
 	</div>
 	<div class="col-lg-3">
-		<img class="media-object img-thumbnail center-block" alt="<?= UOJUserBlog::id() ?> Avatar" src="<?= HTML::avatar_addr(UOJUserBlog::user(), 512) ?>" />
+		<img class="media-object img-thumbnail center-block uoj-user-avatar" alt="<?= UOJUserBlog::id() ?> Avatar" src="<?= HTML::avatar_addr(UOJUserBlog::user(), 512) ?>" />
 		<?php if (UOJUserBlog::userCanManage(Auth::user()) && UOJUser::checkPermission(Auth::user(), 'blogs.create')) : ?>
 			<div class="btn-group d-flex mt-3">
 				<a href="<?= HTML::blog_url(UOJUserBlog::id(), '/post/new/write') ?>" class="btn btn-primary">
diff --git a/web/app/controllers/user_msg.php b/web/app/controllers/user_msg.php
index 7c3f036..0b2934c 100644
--- a/web/app/controllers/user_msg.php
+++ b/web/app/controllers/user_msg.php
@@ -256,7 +256,7 @@ if (isset($_POST['user_msg'])) {
 			'<div class="list-group-item list-group-item-action p-2 d-flex ' + (type ? 'list-group-item-warning' : '') + '" style="cursor: pointer; user-select: none;" ' +
 			'onclick="enterConversation(\'' + conversationName + '\')">' +
 			'<div class="flex-shrink-0 me-3">' +
-			'<img class="rounded" width="56" height="56" src="' + avatar_addr + '" />' +
+			'<img class="rounded uoj-user-avatar" width="56" height="56" src="' + avatar_addr + '" />' +
 			'</div>' +
 			'<div class="flex-grow-1 overflow-hidden">' +
 			'<div class="d-flex justify-content-between">' +
@@ -290,7 +290,7 @@ if (isset($_POST['user_msg'])) {
 				'<span class="float-end" data-bs-toggle="tooltip" data-bs-title="' + read_time + '"><i class="bi bi-check2-all"></i></span>') +
 			'</div>' +
 			'</div>' +
-			(type ? '<img class="flex-shrink-0 ms-2 rounded" width="32" height="32" src="' + user_avatar + '" style="user-select: none;" />' : '') +
+			(type ? '<img class="flex-shrink-0 ms-2 rounded uoj-user-avatar" width="32" height="32" src="' + user_avatar + '" style="user-select: none;" />' : '') +
 			'</div>'
 		);
 	}
diff --git a/web/app/models/UOJRanklist.php b/web/app/models/UOJRanklist.php
index d356291..60cc217 100644
--- a/web/app/models/UOJRanklist.php
+++ b/web/app/models/UOJRanklist.php
@@ -54,7 +54,7 @@ class UOJRanklist {
             <div class="list-group-item">
                 <div class="d-flex">
                     <div class="flex-shrink-0">
-                        <a href="{$userpro}"><img class="rounded" src="{$asrc}" width="50" height="50" /></a>
+                        <a href="{$userpro}"><img class="rounded uoj-user-avatar" src="{$asrc}" width="50" height="50" /></a>
                     </div>
                     <div class="flex-grow-1 ms-3">
                         <div class="row">
diff --git a/web/app/views/blog-nav.php b/web/app/views/blog-nav.php
index 256be0e..3344181 100644
--- a/web/app/views/blog-nav.php
+++ b/web/app/views/blog-nav.php
@@ -3,7 +3,7 @@
 	<div class="container">
 
 		<a class="navbar-brand" href="<?= HTML::blog_url(UOJUserBlog::id(), '/') ?>">
-			<img src="<?= HTML::avatar_addr(UOJUserBlog::user(), 48) ?>" alt="Logo" width="24" height="24" class="d-inline-block align-text-top" />
+			<img src="<?= HTML::avatar_addr(UOJUserBlog::user(), 48) ?>" alt="Logo" width="24" height="24" class="d-inline-block align-text-top uoj-user-avatar" />
 			<?= UOJUserBlog::id() ?>
 		</a>
 
diff --git a/web/app/views/user-info.php b/web/app/views/user-info.php
index 3313c77..6cb986f 100644
--- a/web/app/views/user-info.php
+++ b/web/app/views/user-info.php
@@ -3,7 +3,7 @@
 <div class="row">
 	<div class="col-md-3">
 		<div class="card">
-			<img class="card-img-top" alt="Avatar of <?= $user['username'] ?>" src="<?= HTML::avatar_addr($user, 512) ?>" />
+			<img class="card-img-top uoj-user-avatar" alt="Avatar of <?= $user['username'] ?>" src="<?= HTML::avatar_addr($user, 512) ?>" />
 			<div class="card-body">
 				<?php if ($user['usergroup'] == 'S') : ?>
 					<span class="badge bg-secondary">
diff --git a/web/js/uoj.js b/web/js/uoj.js
index aeb6a77..799d258 100644
--- a/web/js/uoj.js
+++ b/web/js/uoj.js
@@ -1772,3 +1772,9 @@ $(document).ready(function() {
 		);
 	});	
 });
+
+$(document).ready(function() {
+	$('img.uoj-user-avatar').on('error', function() {
+		$(this).attr('src', 'data:image/svg+xml;base64,PHN2ZyB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmciIHZpZXdCb3g9IjAgMCA4NzIgODcyIj48cGF0aCBmaWxsPSIjZmZmIiBkPSJNMCAwaDg3MnY4NzJIMHoiLz48cGF0aCBmaWxsPSIjYzVjNWM1IiBkPSJNMCAwdjg3MmgxMTBhMzI3IDM4MyAwIDAxMjM2LTM0NSAxOTUgMTk1IDAgMDEtMTA0LTE3MiAxOTUgMTk1IDAgMDExOTUtMTk1IDE5NSAxOTUgMCAwMTE5NSAxOTUgMTk1IDE5NSAwIDAxLTEwNiAxNzMgMzI3IDM4MyAwIDAxMjM2IDM0NGgxMTBWMHoiLz48L3N2Zz4=');
+	});
+});