[release-notes/gnome-3-20] provide a gtk banner

[Jakub Steiner <jimmac src gnome org>]

commit 4e3bd8dfcf32c63a56a54b1656e40627ce9d861d
Author: Jakub Steiner <jimmac gmail com>
Date:   Wed Mar 23 12:51:26 2016 +0100

    provide a gtk banner

 help/C/developers.page     |    3 ++-
 help/C/figures/gtk-css.png |  Bin 0 -> 18086 bytes
 help/Makefile.am           |    3 ++-
 3 files changed, 4 insertions(+), 2 deletions(-)
---
diff --git a/help/C/developers.page b/help/C/developers.page
index dbfb60d..bbbb924 100644
--- a/help/C/developers.page
+++ b/help/C/developers.page
@@ -132,7 +132,7 @@
 
   <section id="gtk+">
     <title>GTK+</title>
-    <media type="image" src="figures/gtk.gif"/>
+    <media type="image" src="figures/gtk-css.png"/>
     <p>3.20 is a big release for GTK+. CSS theming has had a major overhaul,
     resulting in significant improvements, with easier theme writing, more
     exact visual styling and more dynamic interfaces. GTK+ themes now
@@ -154,6 +154,7 @@
       <code>radial-gradient()</code>, <code>rem</code> and <code>calc()</code>.
       </p></item>
     </list>
+    <media type="image" src="figures/gtk.gif"/>
     <p>As a result of these changes, existing GTK+ themes will need to be
     updated, and many style properties have been deprecated in favor of CSS
     equivalents. The 3.20 CSS API will remain stable going forward, though (and
diff --git a/help/C/figures/gtk-css.png b/help/C/figures/gtk-css.png
new file mode 100644
index 0000000..40a160a
Binary files /dev/null and b/help/C/figures/gtk-css.png differ
diff --git a/help/Makefile.am b/help/Makefile.am
index ae4756b..b23741a 100644
--- a/help/Makefile.am
+++ b/help/Makefile.am
@@ -25,11 +25,12 @@ HELP_MEDIA = \
  figures/xdg-app.png \
  figures/cantarell.png \
  figures/gtk-inspector.png \
+ figures/gtk-css.png \
  figures/polari.png \
  figures/builder.png \
  figures/os-upgrades.png \
  figures/software-reviews.png \
- figures/software-reviews-header.png
+ figures/software-reviews-header.png \
  figures/gtk.gif
 
 HELP_LINGUAS = cs de es fr gl hu ja ko lt pl pt_BR sv tr uk