diff --git a/src/main/scala/gitbucket/core/view/AvatarImageProvider.scala b/src/main/scala/gitbucket/core/view/AvatarImageProvider.scala
index 8d316ab..8cd64d0 100644
--- a/src/main/scala/gitbucket/core/view/AvatarImageProvider.scala
+++ b/src/main/scala/gitbucket/core/view/AvatarImageProvider.scala
@@ -20,7 +20,7 @@
         if(account.image.isEmpty && context.settings.gravatar){
           s"""https://www.gravatar.com/avatar/${StringUtil.md5(account.mailAddress.toLowerCase)}?s=${size}&d=retro&r=g"""
         } else {
-          s"""${context.path}/${account.userName}/_avatar"""
+          s"""${context.path}/${account.userName}/_avatar?${helpers.hashDate(account.updatedDate)}"""
         }
       } getOrElse {
         s"""${context.path}/_unknown/_avatar"""
@@ -31,7 +31,7 @@
         if(account.image.isEmpty && context.settings.gravatar){
           s"""https://www.gravatar.com/avatar/${StringUtil.md5(account.mailAddress.toLowerCase)}?s=${size}&d=retro&r=g"""
         } else {
-          s"""${context.path}/${account.userName}/_avatar"""
+          s"""${context.path}/${account.userName}/_avatar?${helpers.hashDate(account.updatedDate)}"""
         }
       } getOrElse {
         if(context.settings.gravatar){
@@ -49,4 +49,4 @@
     }
   }
 
-}
\ No newline at end of file
+}
diff --git a/src/main/scala/gitbucket/core/view/helpers.scala b/src/main/scala/gitbucket/core/view/helpers.scala
index dc4e1c1..a60dcbb 100644
--- a/src/main/scala/gitbucket/core/view/helpers.scala
+++ b/src/main/scala/gitbucket/core/view/helpers.scala
@@ -75,6 +75,11 @@
   def date(date: Date): String = new SimpleDateFormat("yyyy-MM-dd").format(date)
 
   /**
+    * Format java.util.Date to "yyyyMMDDHHmmss" (for url hash ex. /some/path.css?19800101010203
+    */
+  def hashDate(date: Date): String = new SimpleDateFormat("yyyyMMddHHmmss").format(date)
+
+  /**
    * Returns singular if count is 1, otherwise plural.
    * If plural is not specified, returns singular + "s" as plural.
    */