Merge pull request #1252 from thedrow/patch-3

Recommend using Pillow instead of PIL.

docs/api-guide/fields.md

@@ -286,7 +286,7 @@ An image representation.
 
 Corresponds to `django.forms.fields.ImageField`.
 
-Requires the `PIL` package.
+Requires either the `Pillow` package or `PIL` package.  The `Pillow` package is recommended, as `PIL` is no longer actively maintained.
 
 Signature and validation is the same as with `FileField`.
 

rest_framework/fields.py

@@ -966,7 +966,7 @@ class ImageField(FileField):
             return None
 
         from rest_framework.compat import Image
-        assert Image is not None, 'PIL must be installed for ImageField support'
+        assert Image is not None, 'Either Pillow or PIL must be installed for ImageField support.'
 
         # We need to get a file object for PIL. We might have a path or we might
         # have to read the data into memory.