diff --git a/app/models/bulletin.rb b/app/models/bulletin.rb
index e8bdd98..bb2db35 100644
--- a/app/models/bulletin.rb
+++ b/app/models/bulletin.rb
@@ -44,6 +44,8 @@ class Bulletin
   
   validates :title, :at_least_one => true
 
+  validate :image_size
+
   # def to_indexed_json
   #   self.to_json
   # end
@@ -171,5 +173,12 @@ class Bulletin
   #   self.tag_ids.delete('')
   # end
 
+  def image_size
+    if self.image.size > 500.kilobyte
+      errors.add( :image,  I18n.t("announcement.image_limit"))
+    end
+  end
+
+
 
 end
diff --git a/app/views/panel/announcement/back_end/bulletins/_form.html.erb b/app/views/panel/announcement/back_end/bulletins/_form.html.erb
index 9ef3a25..6a74470 100644
--- a/app/views/panel/announcement/back_end/bulletins/_form.html.erb
+++ b/app/views/panel/announcement/back_end/bulletins/_form.html.erb
@@ -139,7 +139,7 @@
               </label>
             </div>
           </div>
-          <div class="image_note"><%= t("announcement.image_note")%></div>
+          <div class="image_note"><br /><%= t("announcement.image_note")%><br /><%= t("announcement.image_size_note")%></div>
         </div>
       </div>
 
diff --git a/config/locales/en.yml b/config/locales/en.yml
index 5f0bb5e..a10a566 100644
--- a/config/locales/en.yml
+++ b/config/locales/en.yml
@@ -28,6 +28,8 @@ en:
       search_result: Search result
     image: Cover image
     image_note: The image will not show in content
+    image_size_note: Limited to 500KB
+    image_limit: Image upload size is limited to 500KB
     link_name: Link Name
     new_bulletin_category: New Bulletin Category
     picture: Cover Picture
diff --git a/config/locales/zh_tw.yml b/config/locales/zh_tw.yml
index 6e7509e..10279c4 100644
--- a/config/locales/zh_tw.yml
+++ b/config/locales/zh_tw.yml
@@ -30,6 +30,8 @@ zh_tw:
       search_result: 搜尋結果頁
     image: 封面圖片
     image_note: 此處上傳的圖片不會在公告內文出現
+    image_size_note: 系統限制上傳500k以下的圖片
+    image_limit: 圖片上傳容量限制為500kB
     link_name: 連結名稱
     new_bulletin_category: 新增公告類別
     picture: 刊頭圖片