diff --git a/app/assets/javascripts/discourse/views/composer_view.js b/app/assets/javascripts/discourse/views/composer_view.js
index 14b1a4d5f8b..d36445af564 100644
--- a/app/assets/javascripts/discourse/views/composer_view.js
+++ b/app/assets/javascripts/discourse/views/composer_view.js
@@ -305,7 +305,12 @@ Discourse.ComposerView = Discourse.View.extend({
         return _this.addMarkdown(html);
       },
       fail: function(e, data) {
-        bootbox.alert(Em.String.i18n('post.errors.upload'));
+        // 413 == entity too large, returned usually from nginx
+        if(data.jqXHR && data.jqXHR.status === 413) {
+          bootbox.alert(Em.String.i18n('post.errors.upload_too_large', {max_size_kb: Discourse.SiteSettings.max_upload_size_kb}));
+        } else {
+          bootbox.alert(Em.String.i18n('post.errors.upload'));
+        }
         return _this.set('loadingImage', false);
       }
     });
diff --git a/app/models/site_setting.rb b/app/models/site_setting.rb
index 6246a4a219d..3015f343bdc 100644
--- a/app/models/site_setting.rb
+++ b/app/models/site_setting.rb
@@ -39,6 +39,8 @@ class SiteSetting < ActiveRecord::Base
   # cf. https://github.com/discourse/discourse/pull/462#issuecomment-14991562
   client_setting(:category_colors, 'BF1E2E|F1592A|F7941D|9EB83B|3AB54A|12A89D|25AAE2|0E76BD|652D90|92278F|ED207B|8C6238|231F20|808281|B3B5B4|283890')
 
+  client_setting(:max_upload_size_kb, 1024)
+
   # settings only available server side
   setting(:auto_track_topics_after, 300000)
   setting(:new_topic_duration_minutes, 60 * 48)
diff --git a/config/locales/client.en.yml b/config/locales/client.en.yml
index 381c2254d92..4cd07acb2b2 100644
--- a/config/locales/client.en.yml
+++ b/config/locales/client.en.yml
@@ -538,6 +538,7 @@ en:
         create: "Sorry, there was an error creating your post. Please try again."
         edit: "Sorry, there was an error editing your post. Please try again."
         upload: "Sorry, there was an error uploading that file. Please try again."
+        upload_too_large: "Sorry, the file you are trying to upload is too big (maximum size is {{max_size_kb}}kb), please resize it and try again."
 
       abandon: "Are you sure you want to abandon your post?"
 
diff --git a/config/locales/server.en.yml b/config/locales/server.en.yml
index 8e4a65f0c29..df313efa325 100644
--- a/config/locales/server.en.yml
+++ b/config/locales/server.en.yml
@@ -424,6 +424,7 @@ en:
     min_body_similar_length: "The minimum length of a post's body before it will be checked for similar topics"
 
     category_colors: "A pipe (|) separated list of hexadecimal color values allowed for categories"
+    max_upload_size_kb: "The maximum size of files we allow users to upload in kb - be sure to configure the limit in nginx (client_max_body_size) / apache or proxy as well."
 
   notification_types:
     mentioned: "%{display_username} mentioned you in %{link}"