diff --git a/wagtail/wagtailimages/fields.py b/wagtail/wagtailimages/fields.py
index 93c0ac950f..2663d6667b 100644
--- a/wagtail/wagtailimages/fields.py
+++ b/wagtail/wagtailimages/fields.py
@@ -49,6 +49,10 @@ class WagtailImageField(ImageField):
             "This file is too big (%%s). Maximum filesize %s."
         ) % max_upload_size_text
 
+        self.error_messages['file_too_large_unknown_size'] = _(
+            "This file is too big. Maximum filesize %s."
+        ) % max_upload_size_text
+
     def check_image_file_format(self, f):
         # Check file extension
         extension = os.path.splitext(f.name)[1].lower()[1:]
diff --git a/wagtail/wagtailimages/tests/test_admin_views.py b/wagtail/wagtailimages/tests/test_admin_views.py
index 10a90941ec..8a4b954bb8 100644
--- a/wagtail/wagtailimages/tests/test_admin_views.py
+++ b/wagtail/wagtailimages/tests/test_admin_views.py
@@ -7,6 +7,7 @@ from django.utils.http import urlquote
 from django.core.urlresolvers import reverse
 from django.contrib.auth.models import Permission
 from django.core.files.uploadedfile import SimpleUploadedFile
+from django.template.defaultfilters import filesizeformat
 
 # Get the chars that Django considers safe to leave unescaped in a URL
 # This list changed in Django 1.8:  https://github.com/django/django/commit/e167e96cfea670422ca75d0b35fe7c4195f25b63
@@ -99,9 +100,11 @@ class TestImageAddView(TestCase, WagtailTestUtils):
 
     @override_settings(WAGTAILIMAGES_MAX_UPLOAD_SIZE=1)
     def test_add_too_large_file(self):
+        file_content = get_test_image_file().file.getvalue()
+
         response = self.post({
             'title': "Test image",
-            'file': SimpleUploadedFile('test.png', get_test_image_file().file.getvalue()),
+            'file': SimpleUploadedFile('test.png', file_content),
         })
 
         # Shouldn't redirect anywhere
@@ -109,8 +112,10 @@ class TestImageAddView(TestCase, WagtailTestUtils):
         self.assertTemplateUsed(response, 'wagtailimages/images/add.html')
 
         # The form should have an error
-        # Note: \xa0 = non-blocking space
-        self.assertFormError(response, 'form', 'file', "This file is too big (1.9\xa0KB). Maximum filesize 1\xa0byte.")
+        self.assertFormError(response, 'form', 'file', "This file is too big ({file_size}). Maximum filesize {max_file_size}.".format(
+            file_size=filesizeformat(len(file_content)),
+            max_file_size=filesizeformat(1),
+        ))
 
 
 class TestImageEditView(TestCase, WagtailTestUtils):
@@ -302,6 +307,13 @@ class TestMultipleImageUploader(TestCase, WagtailTestUtils):
         self.assertEqual(response.status_code, 200)
         self.assertTemplateUsed(response, 'wagtailimages/multiple/add.html')
 
+    @override_settings(WAGTAILIMAGES_MAX_UPLOAD_SIZE=1000)
+    def test_add_max_file_size_context_variables(self):
+        response = self.client.get(reverse('wagtailimages_add_multiple'))
+
+        self.assertEqual(response.context['max_filesize'], 1000)
+        self.assertEqual(response.context['error_max_file_size'], "This file is too big. Maximum filesize 1000\xa0bytes.")
+
     def test_add_post(self):
         """
         This tests that a POST request to the add view saves the image and returns an edit form
diff --git a/wagtail/wagtailimages/views/multiple.py b/wagtail/wagtailimages/views/multiple.py
index 29eb9ae5d5..13142aa44a 100644
--- a/wagtail/wagtailimages/views/multiple.py
+++ b/wagtail/wagtailimages/views/multiple.py
@@ -88,7 +88,7 @@ def add(request):
         'max_filesize': form.fields['file'].max_upload_size,
         'help_text': form.fields['file'].help_text,
         'allowed_extensions': ALLOWED_EXTENSIONS,
-        'error_max_file_size': form.fields['file'].error_messages['file_too_large'],
+        'error_max_file_size': form.fields['file'].error_messages['file_too_large_unknown_size'],
         'error_accepted_file_types': form.fields['file'].error_messages['invalid_image'],
     })