From 4cc1549b6ebfe8983ee2fd4b9be973448f2d0e0b Mon Sep 17 00:00:00 2001
From: Hasan Ramezani <hasan.r67@gmail.com>
Date: Fri, 25 Oct 2019 14:57:37 +0200
Subject: [PATCH] [2.2.x] Fixed #13750 -- Clarified need to reopen
 models.ImageField.image file to access raw image data.

Backport of f57e174fa61e4c31213f6d0033fb9d647b463626 from master
---
 docs/topics/files.txt | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/docs/topics/files.txt b/docs/topics/files.txt
index 67ce56adcd..58bf9b7715 100644
--- a/docs/topics/files.txt
+++ b/docs/topics/files.txt
@@ -73,6 +73,27 @@ location (:setting:`MEDIA_ROOT` if you are using the default
     >>> car.photo.path == new_path
     True
 
+.. note::
+
+    Whilst :class:`~django.db.models.ImageField` non-image data attributes,
+    such as ``height``, ``width``, and ``size`` are available on the instance,
+    the underlying image data cannot be used without reopening the image. For
+    example::
+
+        >>> from PIL import Image
+        >>> car = Car.objects.get(name='57 Chevy')
+        >>> car.photo.width
+        191
+        >>> car.photo.height
+        287
+        >>> image = Image.open(car.photo)
+        # Raises ValueError: seek of closed file.
+        >>> car.photo.open()
+        <ImageFieldFile: cars/chevy.jpg>
+        >>> image = Image.open(car.photo)
+        >>> image
+        <PIL.JpegImagePlugin.JpegImageFile image mode=RGB size=1600x1200 at 0x7F99A94E9048>
+
 The ``File`` object
 ===================