diff --git a/wagtail/wagtailimages/static/wagtailimages/js/add-multiple.js b/wagtail/wagtailimages/static/wagtailimages/js/add-multiple.js
index 05c72feb4..962af60cd 100644
--- a/wagtail/wagtailimages/static/wagtailimages/js/add-multiple.js
+++ b/wagtail/wagtailimages/static/wagtailimages/js/add-multiple.js
@@ -15,6 +15,7 @@ $(function(){
         sequentialUploads: true,
         dropZone: $('.drop-zone'),
         acceptFileTypes: /(\.|\/)(gif|jpe?g|png)$/i,
+        maxFileSize: window.max_file_size,
         previewMinWidth:150,
         previewMaxWidth:150,
         previewMinHeight:150,
diff --git a/wagtail/wagtailimages/templates/wagtailimages/multiple/add.html b/wagtail/wagtailimages/templates/wagtailimages/multiple/add.html
index 066650d83..1859b68ce 100644
--- a/wagtail/wagtailimages/templates/wagtailimages/multiple/add.html
+++ b/wagtail/wagtailimages/templates/wagtailimages/multiple/add.html
@@ -69,6 +69,7 @@
 
     {% url 'wagtailadmin_tag_autocomplete' as autocomplete_url %}
     <script>
+        window.max_file_size = {{ max_filesize }};
         window.simple_upload_url = "{% url 'wagtailimages_add_image' %}";
         window.tagit_opts = {
             autocomplete: {source: "{{ autocomplete_url|addslashes }}"}
diff --git a/wagtail/wagtailimages/utils/validators.py b/wagtail/wagtailimages/utils/validators.py
index 5228cc479..9b8bcc8ab 100644
--- a/wagtail/wagtailimages/utils/validators.py
+++ b/wagtail/wagtailimages/utils/validators.py
@@ -16,7 +16,7 @@ def validate_image_format(f):
         extension = 'jpeg'
 
     if extension not in ['gif', 'jpeg', 'png']:
-        raise ValidationError(_("Not a valid image. Please use a gif, jpeg or png file with the correct file extension (*.gif, *.jpg or *.png)."))
+        raise ValidationError(_("Not a supported image type. Please use a gif, jpeg or png file with the correct file extension (*.gif, *.jpg or *.png)."))
 
     if not f.closed:
         # Open image file