doc: add overview of all templates

Author: peterpeterparker

doc/slides/slides.md

@@ -6,12 +6,47 @@ Some templates offer extra features as for example the slide [Code](#slide-code)
 
 ## Table of contents
 
+- [Overview](#overview)
 - [Slide: Title](#slide-title)
 - [Slide: Content](#slide-content)
 - [Slide: Split](#slide-split)
 - [Slide: Code](#slide-code)
 - [Slide: Author](#slide-author)
 
+## Overview
+
+[DeckDeckGo] provide the following templates:
+
+<div style="display: grid; grid-template-columns: 30% 30% 30%; grid-gap: 10px;">
+  <div style="display: flex; flex-direction: column;">
+    <img src="https://github.com/fluster/deckdeckgo/blob/master/doc/slides/deckdeckgo-slide-title-layout.png" width="250px">
+    <p>"Title"</p>
+  </div>
+  
+  <div style="display: flex; flex-direction: column;">
+    <img src="https://github.com/fluster/deckdeckgo/blob/master/doc/slides/deckdeckgo-slide-content-layout.png" width="250px">
+    <p>"Content"</p>
+  </div>
+  
+  <div style="display: flex; flex-direction: column;">
+    <img src="https://github.com/fluster/deckdeckgo/blob/master/doc/slides/deckdeckgo-slide-split-layout.png" width="250px">
+    <p>"Split"</p>
+  </div>
+  
+  <div style="display: flex; flex-direction: column;">
+    <img src="https://github.com/fluster/deckdeckgo/blob/master/doc/slides/deckdeckgo-slide-code-layout.gif" width="250px">
+    <p>"Code"</p>
+  </div>
+  
+  <div style="display: flex; flex-direction: column;">
+    <img src="https://github.com/fluster/deckdeckgo/blob/master/doc/slides/deckdeckgo-slide-split-author.png" width="250px">
+    <p>"Author"</p>
+  </div>
+
+</div>
+
+*Note: If you would miss or need further templates, don't hesitate to open an issue and/or submit a PR, it would be my pleasure to add more options*
+
 ## Slide: Title
 
 The "Title" slide is a simple slide which display its title and content center in the middle of the page.