diff --git a/markdownx/forms.py b/markdownx/forms.py
index 1905efd..c52e90d 100755
--- a/markdownx/forms.py
+++ b/markdownx/forms.py
@@ -54,7 +54,7 @@ class ImageForm(forms.Form):
         content_type = image.content_type
         file_name = image.name
         image_extension = content_type.split('/')[-1].upper()
-        image_size = getattr(image, '_size')
+        image_size = image.size
 
         if content_type.lower() != self._SVG_TYPE:
             # Processing the raster graphic image.
@@ -176,7 +176,7 @@ class ImageForm(forms.Form):
             raise MarkdownxImageUploadError.not_uploaded()
 
         content_type = upload.content_type
-        file_size = getattr(upload, '_size')
+        file_size = upload.size
 
         if content_type not in MARKDOWNX_UPLOAD_CONTENT_TYPES:
 
diff --git a/markdownx/tests/static/django-markdownx-preview.png b/markdownx/tests/static/django-markdownx-preview.png
new file mode 100644
index 0000000..769556b
Binary files /dev/null and b/markdownx/tests/static/django-markdownx-preview.png differ
diff --git a/markdownx/tests/tests.py b/markdownx/tests/tests.py
index 63e2174..2b0345c 100644
--- a/markdownx/tests/tests.py
+++ b/markdownx/tests/tests.py
@@ -1,4 +1,10 @@
+import os
+import re
 from django.test import TestCase
+try:
+    from django.urls import reverse
+except ImportError:  # Djanago < 2.0
+    from django.core.urlresolvers import reverse
 
 
 class SimpleTest(TestCase):
@@ -6,3 +12,24 @@ class SimpleTest(TestCase):
     def test_me(self):
         response = self.client.get('/testview/')
         self.assertEqual(response.status_code, 200)
+
+    def test_upload(self):
+        url = reverse('markdownx_upload')
+        with open('markdownx/tests/static/django-markdownx-preview.png', 'rb') as fp:
+            response = self.client.post(url, {'image': fp}, HTTP_X_REQUESTED_WITH='XMLHttpRequest')
+
+        try:
+            json = response.json()
+        except AttributeError:  # Django < 1.9
+            import json
+            json = json.loads(response.content.decode('utf-8'))
+
+        self.assertEqual(response.status_code, 200)
+        self.assertIn('image_code', json)
+
+        match = re.findall(r'(markdownx/[\w\-]+\.png)', json['image_code'])
+        try:
+            if match:
+                os.remove(match[0])
+        except OSError:
+            pass