Merge branch 'master' into refs-nitpick

docs/reference/Image.rst

@@ -330,6 +330,36 @@ Instances of the :py:class:`Image` class have the following attributes:
 
     Unless noted elsewhere, this dictionary does not affect saving files.
 
+.. py:attribute:: Image.is_animated
+    :type: bool
+
+    ``True`` if this image has more than one frame, or ``False`` otherwise.
+
+    This attribute is only defined by image plugins that support animated images.
+    Plugins may leave this attribute undefined if they don't support loading
+    animated images, even if the given format supports animated images.
+
+    Given that this attribute is not present for all images use
+    ``getattr(image, "is_animated", False)`` to check if Pillow is aware of multiple
+    frames in an image regardless of its format.
+
+    .. seealso:: :attr:`~Image.n_frames`, :func:`~Image.seek` and :func:`~Image.tell`
+
+.. py:attribute:: Image.n_frames
+    :type: int
+
+    The number of frames in this image.
+
+    This attribute is only defined by image plugins that support animated images.
+    Plugins may leave this attribute undefined if they don't support loading
+    animated images, even if the given format supports animated images.
+
+    Given that this attribute is not present for all images use
+    ``getattr(image, "n_frames", 1)`` to check the number of frames that Pillow is
+    aware of in an image regardless of its format.
+
+    .. seealso:: :attr:`~Image.is_animated`, :func:`~Image.seek` and :func:`~Image.tell`
+
 Classes
 -------
 

src/PIL/Image.py

@@ -2177,6 +2177,9 @@ class Image:
 
         See :py:meth:`~PIL.Image.Image.tell`.
 
+        If defined, :attr:`~PIL.Image.Image.n_frames` refers to the
+        number of available frames.
+
         :param frame: Frame number, starting at 0.
         :exception EOFError: If the call attempts to seek beyond the end
             of the sequence.
@@ -2261,6 +2264,9 @@ class Image:
         """
         Returns the current frame number. See :py:meth:`~PIL.Image.Image.seek`.
 
+        If defined, :attr:`~PIL.Image.Image.n_frames` refers to the
+        number of available frames.
+
         :returns: Frame number, starting with 0.
         """
         return 0