Add commands for navigating multi-frame images

* lisp/image.el (image-nth-frame): New, split from image-animate-timeout.
(image-animate-timeout): Use image-nth-frame.

* lisp/image-mode.el (image-goto-frame, image-next-frame)
(image-previous-frame): New commands.
(image-mode-map): Add new frame commands.

* etc/NEWS: Mention this.

1 files changed, 4 insertions, 0 deletions

diff --git a/etc/NEWS b/etc/NEWS
index 98824220cec..62d84a0788d 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -141,6 +141,10 @@ amounts of data into the ERC input.
 visit the next image file and the previous image file in the same
 directory, respectively.
 
+*** New commands to show specific frames of multi-frame images.
+`f' (`image-next-frame') and `b' (`image-previous-frame') visit the
+next or previous frame.  `F' (`image-goto-frame') shows a specific frame.
+
 ---
 *** The command `image-mode-fit-frame' deletes other windows.
 When toggling, it restores the frame's previous window configuration.