[Pound Mailing List] Proxy a request to new URL

Hi,
I am attempting to proxy some image files from an old URL to the new while redirecting the old URL to the new. See below:

Old URL: example.com/old/images/image.gif
New URL: example.com/new/app/images/image.gif

This configuration:
Service
     URL "^/old.*"
     Redirect "https://example.com/new/app"
End

Only redirects me to the home page of the new URL (https://example.com/new/app), and the end of the URI (/images/image.gif) is lost.

How can I get pound to redirect to the new URL and keep the end of the URI string?

Thanks!
Alex