Fixed post admin

boards/admin.py

@@ -44,7 +44,7 b' class PostAdmin(admin.ModelAdmin):'
         image_urls = ['<a href="{}"><img src="{}" /></a>'.format(
             reverse('admin:%s_%s_change' % (image._meta.app_label,
                                             image._meta.model_name),
-                    args=[image.id]), image.file.url_200x150) for image in images]
+                    args=[image.id]), image.get_thumb_url()) for image in images]
         return ', '.join(image_urls)
     linked_images.allow_tags = True