Q: Apache::mod_proxy how implement request forward for image files

[Snow Leopard <snow.leopard.deb@gmail.com>]

Hello,

Can somebody explain how next task can be accomplished? My own attempt 
to figure out how this can be achieved wasn't successful.

I do not see any problem with virtual servers. But how to implement in 
apache2 through mod_proxy forwarding for image files requests only? And 
how on backend virtual server exclude/blocks a requests for all types of 
files except pictures?

 Create a new Apache VirtualHost that meets the following requirements:
            Name: frontend.${IP}.example.com
            Port: 80
            Document Root: /var/www/vhosts/frontend/htdocs
            Using Mod Proxy, forward all requests for image files 
(.jpg, .gif, or .png) to the backend server without modifying the URL of 
the request
            All errors should log to 
/var/www/vhosts/frontend/logs/error.log
            All access requests should be logged to 
/var/www/vhosts/frontend/logs/access.log except for requests for any 
files ending in .jpg, .gif, .png.

        Backend Site

        Create another Apache VirtualHost that meets the following 
requirements:
            Name: backend.${IP}.example.com
            Port: 8001
            Document Root: /var/www/vhosts/backend/htdocs
            Configure this VirtualHost to respond with a 403 Forbidden 
error for all requests for files that do not contain an extension of 
.jpg, .gif, or .png


Thank you in advance,
Andy