Help/About: Add illustrations to the Get Involved tab.

Follow-up to [56220], [56227], [56233], [56234], [56259].

Props richtabor, markoserb.
Reviewed by peterwilsoncc, audrasjb.
Merges [56290] to the 6.3 branch.
Fixes #23348.




git-svn-id: https://develop.svn.wordpress.org/branches/6.3@56293 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-admin/contribute.php

@@ -40,7 +40,7 @@ require_once ABSPATH . 'wp-admin/admin-header.php';
 
 	<div class="about__section has-2-columns is-wider-right">
 		<div class="column about__image">
-			<img src="data:image/svg+xml,%3Csvg width='436' height='436' viewbox='0 0 100 100' xmlns='http://www.w3.org/2000/svg'%3E%3Crect width='100%25' height='100%25' fill='%231d35b4' /%3E%3C/svg%3E" alt="" />
+			<img src="<?php echo esc_url( admin_url( 'images/contribute-main.svg?ver=6.3' ) ); ?>" alt="" />
 		</div>
 		<div class="column is-vertically-aligned-center">
 			<p><?php _e( 'Do you use WordPress for work, for personal projects, or even just for fun? You can help shape the long-term success of the open source project that powers millions of websites around the world.' ); ?></p>
@@ -72,12 +72,12 @@ require_once ABSPATH . 'wp-admin/admin-header.php';
 			</ul>
 		</div>
 		<div class="column">
-			<img src="data:image/svg+xml,%3Csvg width='436' height='300' viewbox='0 0 100 100' xmlns='http://www.w3.org/2000/svg'%3E%3Crect width='100%25' height='100%25' fill='%231d35b4' /%3E%3C/svg%3E" alt="" />
+			<img src="<?php echo esc_url( admin_url( 'images/contribute-no-code.svg?ver=6.3' ) ); ?>" alt="" />
 		</div>
 	</div>
 	<div class="about__section has-2-columns is-wider-right">
 		<div class="column">
-			<img src="data:image/svg+xml,%3Csvg width='436' height='300' viewbox='0 0 100 100' xmlns='http://www.w3.org/2000/svg'%3E%3Crect width='100%25' height='100%25' fill='%231d35b4' /%3E%3C/svg%3E" alt="" />
+			<img src="<?php echo esc_url( admin_url( 'images/contribute-code.svg?ver=6.3' ) ); ?>" alt="" />
 		</div>
 		<div class="column is-vertically-aligned-center">
 			<h3><?php _e( 'Code-based contribution' ); ?></h3>