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.

next/pw-change.html

@@ -430,35 +430,39 @@ email in <a href="../quick-start.html#step_3">step 3</a>, you need to login to t
 server</a>.</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 ready for submissions <strong>ONLY WHEN THE CONTEST IS <a href="../faq.html#open">open</a></strong>.
-See <a href="../status.html">current status of the IOCCC</a> for details on the contest status.</p>
+<p><strong>NOTE</strong>: The <a href="https://submit.ioccc.org">IOCCC submit server</a> will be ready
+for submissions <strong>ONLY WHEN THE CONTEST IS <a href="../faq.html#open">open</a></strong>. See
+<a href="../status.html">current status of the IOCCC</a> for details on the contest status.</p>
 <p><strong>IMPORTANT NOTE</strong>: When the contest is <a href="../faq.html#closed">closed</a>, the
 <a href="https://submit.ioccc.org">IOCCC submit server</a>
-may be offline and unreachable as a web site.</p>
+may be offline and unreachable as a website.</p>
 <p>To login and change your password, open <a href="https://submit.ioccc.org">https://submit.ioccc.org</a>
 in your browser. It should look like this:</p>
-<p><img src="../png/submit-server-login.png"
+<p><img src="../png/submit.login.png"
  alt="submit server login screen"
  width=710 height=562></p>
-<p>The username is the UUID you were provided when you registered for the IOCCC and
-the password is the initial password you were provided with. Click “Login”.</p>
-<p>If this is the first time you have logged in with this UUID, you will
-be required to change your password.</p>
-<p>Assuming everything is fine, it should look something like:</p>
-<p><img src="../png/submit-server-first-login.png"
+<p>The username is the UUID you are provided when a judge replies to your request
+to register for the IOCCC and the password is the initial password you are
+given. Click “Login”.</p>
+<p>After you log in, if this is the first time you have logged in with this UUID,
+you will be required to change your password. Assuming everything is fine, that
+would look something like:</p>
+<p><img src="../png/submit.first-login.png"
  alt="submit server password change required"
  width=710 height=808></p>
-<p>As you can see, you have to change your password. Put in your login (UUID
-username), your old (initial) password and a new password. For instance:</p>
-<p><img src="../png/submit-server-change-passwd.png"
- alt="submit server changing password"
- width=710 height=808></p>
+<p>As you can see, on your first login you <strong>MUST</strong> change your password. If you do
+not do this within 72 hours <strong>YOUR ACCOUNT WILL BE CLOSED</strong> and you’ll have to
+register again!</p>
+<p>Put in your login (UUID username), your old (initial) password and a new password.</p>
 <p>Click “Change Password”.</p>
-<p>Once this is done, you will be able to log in again with your UUID
+<p><strong>NOTE</strong>: if you have put in your old password, you’ll see something like:</p>
+<p><img src="../png/submit.invalid-passwd.png"
+ alt="submit server password change error"
+ width=710 height=808></p>
+<p>Once you’ve changed your password you will be able to log in again with your UUID
 username and new password. This is what it will look like when you change your
 password:</p>
-<p><img src="../png/submit-server-passwd-changed.png"
+<p><img src="../png/submit.passwd-changed.png"
  alt="submit server password changed"
  width=710 height=344></p>
 <p>When the contest is <a href="../faq.html#open">open</a>, proceed with