[release-notes/gnome-3-16] add a screenshot for gtk

[Allan Day <allanday src gnome org>]

commit 3139cbd5c38ce201cafd96fc46e1dbe2b02b875b
Author: Allan Day <allanpday gmail com>
Date:   Thu Mar 19 12:36:44 2015 +0000

    add a screenshot for gtk

 help/C/developers.page |    2 +-
 help/C/figures/gtk.png |  Bin 0 -> 628609 bytes
 help/Makefile.am       |    1 +
 3 files changed, 2 insertions(+), 1 deletions(-)
---
diff --git a/help/C/developers.page b/help/C/developers.page
index 721e593..20ed3dd 100644
--- a/help/C/developers.page
+++ b/help/C/developers.page
@@ -27,7 +27,7 @@
 
   <section id="gtk+">
     <title>GTK+</title>
-    <media type="image" src="figures/placeholder.png"/>
+    <media type="image" src="figures/gtk.png"/>
     <p>With &gnomeversion;, built-in <link href="https://en.wikipedia.org/wiki/OpenGL";>OpenGL</link> support 
has arrived for GTK+. This allows applications that make heavy use of 3D graphics to be written in 
conjunction with GTK+, using the new <code>GtkGLArea</code> widget. OpenGL support in GTK+ &gnomeversion; 
provides an effective replacement for the previous GtkGLArea and GtkGLExt libraries.</p>
 
    <p>Other changes in this version of GTK+ include:</p>
diff --git a/help/C/figures/gtk.png b/help/C/figures/gtk.png
new file mode 100644
index 0000000..23844bb
Binary files /dev/null and b/help/C/figures/gtk.png differ
diff --git a/help/Makefile.am b/help/Makefile.am
index 3593726..1a9a835 100644
--- a/help/Makefile.am
+++ b/help/Makefile.am
@@ -22,6 +22,7 @@ HELP_MEDIA = \
  figures/taquin.png \
  figures/overlay-scrollbars.png \
  figures/maps.png \
+ figures/gtk.png \
  figures/wayland.png
 
 HELP_LINGUAS = es fr gl pl tr uk