Update screenshots and files that reference them

The screenshots are more recent (including some new ones).

The welcome email images have not been updated as some things have to be
answered before that can be done.

The current files were renamed to be shorter as well.

quick-start.html

@@ -485,7 +485,7 @@ for assistance.</p>
 <p><strong>IMPORTANT NOTE</strong>: You must change your password <strong>WITHIN 72 HOURS</strong>
 from when one of the <a href="judges.html">IOCCC judges</a> sent that email.</p>
 <p><strong>NOTE</strong>: The <a href="https://submit.ioccc.org">IOCCC submit server</a>
-is only ready for submissions <strong>ONLY WHEN THE CONTEST IS <a href="faq.html#open">open</a></strong>.</p>
+is ready for submissions <strong>ONLY WHEN THE CONTEST IS <a href="faq.html#open">open</a></strong>.</p>
 <p>Please visit the “<strong><a href="next/pw-change.html">change your submit server initial password</a></strong>” page for detailed instructions.</p>
 <div id="step_5">
 <h2 id="obtain-and-compile-the-latest-mkiocccentry-toolkit">5. Obtain and compile the latest mkiocccentry toolkit</h2>