I create a empty album or there is only video,and no photo in this ablum,then the album thumbnail will be the "zen-logo.jpg" if "mod_rewrite" is off.it's address like
http://localhost/zp-core/i.php?a=&i=zen-logo.jpg&s=thumb

but if "mod_rewrite" is on ,it can not display exactly ,instead of a red furcation,that means the program does not find the picture "zen-logo.jpg"

the code in ".htaccess"
RewriteRule ^(.)/image/(thumb|[0-9]{1,4})/([^/\]+)$ zp-core/i.php?a=$1&i=$3&s=$2 [L,QSA]
RewriteRule ^(.)/image/([^/\]+)$ zp-core/i.php?a=$1&i=$2 [L,QSA]

I think there is something wrong in this code,but I do not know how to fix it.

When mod_rewrite is on what does the url look like?

Also, what version of zenphoto are you running?

http://localhost/%20/image/thumb/zen-logo.jpg
that album's name is "FLV"