diff --git a/installing-python.html b/installing-python.html
index 3e60e34..846acd8 100644
--- a/installing-python.html
+++ b/installing-python.html
@@ -24,31 +24,31 @@ body{counter-reset:h1 0}
 
 <h2 id=windows>Installing on Microsoft Windows</h2>
 
-<p><img src=i/win-install-0-security-warning.png>
-<p><img src=i/win-install-1-all-users-or-just-me.png>
-<p><img src=i/win-install-2-destination-directory.png>
-<p><img src=i/win-install-3-customize.png>
-<p><img src=i/win-install-3a-disk-usage.png>
-<p><img src=i/win-install-3b-test-suite.png>
-<p><img src=i/win-install-4-copying.png>
-<p><img src=i/win-install-5-finish.png>
-<p><img src=i/win-interactive-shell.png>
+<p><img src=i/win-install-0-security-warning.png width=409 height=309 alt='[Windows dialog: open file security warning]'>
+<p><img src=i/win-install-1-all-users-or-just-me.png width=499 height=432 alt='[Python installer: select whether to install Python 3.1 for all users of this computer]'>
+<p><img src=i/win-install-2-destination-directory.png width=499 height=432 alt='[Python installer: select destination directory]'>
+<p><img src=i/win-install-3-customize.png width=499 height=432 alt='[Python installer: customize Python 3.1]'>
+<p><img src=i/win-install-3a-disk-usage.png width=499 height=432 alt='[Python installer: disk space requirements]'>
+<p><img src=i/win-install-3b-test-suite.png width=499 height=432 alt='[Python installer: removing Test Suite option will save 7908KB on your hard drive]'>
+<p><img src=i/win-install-4-copying.png width=499 height=432 alt='[Python installer: progress meter]'>
+<p><img src=i/win-install-5-finish.png width=499 height=432 alt='[Python installer: installation completed]'>
+<p><img src=i/win-interactive-shell.png width=677 height=715 alt='[Python Shell, a graphical interactive shell for Python]'>
 
 <h2 id=macosx>Installing on Mac OS X</h2>
 
-<p><img src=i/mac-install-0-dmg-contents.png>
-<p><img src=i/mac-install-1-welcome.png>
-<p><img src=i/mac-install-2-information.png>
-<p><img src=i/mac-install-3-license.png>
-<p><img src=i/mac-install-4-license-dialog.png>
-<p><img src=i/mac-install-5-standard-install.png>
-<p><img src=i/mac-install-6-custom-install.png>
-<p><img src=i/mac-install-7-admin-password.png>
-<p><img src=i/mac-install-8-progress.png>
-<p><img src=i/mac-install-9-succeeded.png>
-<p><img src=i/mac-install-10-application-folder.png>
-<p><img src=i/mac-interactive-shell.png>
-<p><img src=i/mac-pythonlauncher.png>
+<p><img src=i/mac-install-0-dmg-contents.png width=752 height=438 alt='[contents of Python installer disk image]'>
+<p><img src=i/mac-install-1-welcome.png width=622 height=442 alt='[Python installer: welcome screen]'>
+<p><img src=i/mac-install-2-information.png width=622 height=442 alt='[Python installer: information about supported architectures, disk space, and acceptable destination folders]'>
+<p><img src=i/mac-install-3-license.png width=622 height=442 alt='[Python installer: software license agreement]'>
+<p><img src=i/mac-install-4-license-dialog.png width=622 height=442 alt='[Python installer: dialog to accept license agreement]'>
+<p><img src=i/mac-install-5-standard-install.png width=622 height=442 alt='[Python installer: standard install screen]'>
+<p><img src=i/mac-install-6-custom-install.png width=622 height=442 alt='[Python installer: custom install screen]'>
+<p><img src=i/mac-install-7-admin-password.png width=622 height=457 alt='[Python installer: dialog to enter administrative password]'>
+<p><img src=i/mac-install-8-progress.png width=622 height=442 alt='[Python installer: progress meter]'>
+<p><img src=i/mac-install-9-succeeded.png width=622 height=442 alt='[Python installer: installation succeeded]'>
+<p><img src=i/mac-install-10-application-folder.png width=448 height=482 alt='[contents of /Applications/Python 3.1/ folder]'>
+<p><img src=i/mac-interactive-shell.png width=522 height=538 alt='[Python Shell, a graphical interactive shell for Python]'>
+<p><img src=i/mac-pythonlauncher.png width=432 height=536 alt='[Python Launcher preferences window]'>
 
 <h2 id=ubuntu>Installing on Ubuntu Linux</h2>