update docs images with white backgrounds

The figures in the documentation are switched to use white backgrounds for better visibility when the user switches the documentation to "night view."

Author: owlang

docusaurus/docs/welcome.md

@@ -4,7 +4,7 @@ title: Welcome
 sidebar_label: Welcome
 ---
 
-![Figure1](/genopipe-img/Figure1.svg)
+<img src={require('/../static/genopipe-img/Figure1.png').default} style={{width:60+'%'}}/>
 
 Welcome to the GenoPipe wiki!