Redirect 404 pages and not images

Hi,

 

Can anybody explain why the following redirects both 404's from missing pages AND missing images, (redirecting when its only a missing image can cause us problems).

 

 

when HTTP_RESPONSE {

 

if { [HTTP::status] ends_with "404" } {

 

if { [HTTP::header "Content-Type"] starts_with "text/" } {

 

HTTP::redirect "http://www.homepage.com/"

 

}

 

}

 

}

 

 

Thanks.