Peter's & WP Super Cache | Peter's Custom Anti-Spam for WordPress | Forum

Try using re-write rules -- maybe it'll fool WP Super Cache to either not cache the image and audio or think they're separate pages:

1) Find the lines that link to the audio file and that load the image file and replace them with the following:

if ($cas_mp3) echo( '<a href="' . $cas_myurl . '/audioselect/' . $cas_rowid . '" title="Hear an audio file of the anti-spam image">' );
echo( '<img src="' . $cas_myurl . '/antiselect/' . $cas_rowid . "\\"\\n\\t\\t\\t\\t" );</code>

2) Add a rewrite rule to the .htaccess file in the root of your blog:

RewriteEngine On
RewriteRule ^antiselect/(.+)$ index.php?antiselect=$1 [L]
RewriteRule ^audioselect/(.+)$ index.php?audioselect=$1 [L]