diff --git a/boards/models/attachment/viewers.py b/boards/models/attachment/viewers.py
--- a/boards/models/attachment/viewers.py
+++ b/boards/models/attachment/viewers.py
@@ -145,7 +145,7 @@ class ImageViewer(AbstractViewer):
     def get_format_view(self):
         metadata = '{}, {}'.format(self.file.name.split('.')[-1],
                                    filesizeformat(self.file.size))
-        width, height = get_image_dimensions(self.file.file)
+        width, height = get_image_dimensions(self.file.path)
         preview_path = self.file.path.replace('.', '.200x150.')
         pre_width, pre_height = get_image_dimensions(preview_path)