[gimp-web] Add a screenshot for themes on 2.99.2

[Jehan <jehanp src gnome org>]

commit ea7943af9ceb1c5f4beb9b38b3bc5eda0d0209de
Author: Jehan <jehan girinstud io>
Date:   Thu Nov 5 21:49:11 2020 +0100

    Add a screenshot for themes on 2.99.2
    
    It's not really about the themes themselves since we don't really have
    themes yet (this mostly shows underlying system theme), but about the
    fact that a single theme can have dark/light variants (which GIMP allows
    to select independently from the OS settings) and that symbolic icons
    are recolored according to theme colors.

 .../gimp-2.99.2-themes.jpg                             | Bin 0 -> 480466 bytes
 .../news/2020/2020-11_GIMP-2.99.2_Released/index.md    |   7 +++++++
 2 files changed, 7 insertions(+)
---
diff --git a/content/news/2020/2020-11_GIMP-2.99.2_Released/gimp-2.99.2-themes.jpg 
b/content/news/2020/2020-11_GIMP-2.99.2_Released/gimp-2.99.2-themes.jpg
new file mode 100644
index 00000000..b3f8f039
Binary files /dev/null and b/content/news/2020/2020-11_GIMP-2.99.2_Released/gimp-2.99.2-themes.jpg differ
diff --git a/content/news/2020/2020-11_GIMP-2.99.2_Released/index.md 
b/content/news/2020/2020-11_GIMP-2.99.2_Released/index.md
index 11a0cfe0..909c9a51 100644
--- a/content/news/2020/2020-11_GIMP-2.99.2_Released/index.md
+++ b/content/news/2020/2020-11_GIMP-2.99.2_Released/index.md
@@ -117,6 +117,13 @@ Similarly icon themes may propose symbolic and color icons.  Once again
 our Icon Theme preferences provides a "*Use symbolic icons if
 available*" checkbox allowing you to indicate your prefered style.
 
+<figure>
+<img src="{attach}gimp-2.99.2-themes.jpg" alt="Theme switching"/>
+<figcaption>
+<em>Switching to Dark or light themes with a single checkbox with icons recoloring to theme colors</em>
+</figcaption>
+</figure>
+
 *Status*: waiting for theme contributors.
 
 On core side, there is not much more to do. Yet you will