I’m having the same problem after setting up the WP 3.0 multisite feature –everything else seems to work except the image upload (it is not shown after upload and also missing in the media list). I followed the .htaccess setting suggested after I created the network (see below). Would appreciate help from the WP forum experts in multisite configuration.
Thank you.
……
RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ - [L]
# uploaded files
RewriteRule ^files/(.+) wp-includes/ms-files.php?file=$1 [L]
RewriteCond %{REQUEST_FILENAME} -f [OR]
RewriteCond %{REQUEST_FILENAME} -d
RewriteRule ^ - [L]
RewriteRule . index.php [L]