Add file_size field to Image

wagtail/wagtailimages/migrations/0007_image_file_size.py

@@ -0,0 +1,19 @@
+# -*- coding: utf-8 -*-
+from __future__ import unicode_literals
+
+from django.db import models, migrations
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('wagtailimages', '0006_add_verbose_names'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='image',
+            name='file_size',
+            field=models.PositiveIntegerField(editable=False, null=True),
+        ),
+    ]

wagtail/wagtailimages/models.py

@@ -71,6 +71,20 @@ class AbstractImage(models.Model, TagSearchable):
     focal_point_width = models.PositiveIntegerField(null=True, blank=True)
     focal_point_height = models.PositiveIntegerField(null=True, blank=True)
 
+    file_size = models.PositiveIntegerField(null=True, editable=False)
+
+    def get_file_size(self):
+        if self.file_size is None:
+            try:
+                self.file_size = self.file.size
+            except OSError:
+                # File doesn't exist
+                return
+
+            self.save(update_fields=['file_size'])
+
+        return self.file_size
+
     def get_usage(self):
         return get_object_usage(self)