This will work if your server is apache with mod_rewrite enabled:
RewriteRule ^photo(.*)$ http://www.example.com/blog/ [R=301,L]
and if upper or lower case characters are acceptable, then use this:
RewriteRule ^photo(.*)$ http://www.example.com/blog/ [R=301,L,NC]
Because of the redirect, I'd recommend using the full absolute URL to redirect to instead of a relative URL because an rfc document (I forgot the rfc number) once stated that the Location header on a redirect page must be a full absolute URL but then another rfc document later stated the URL can be relative, but if you want to increase compatibility for every web browser, I'd suggest using absolute URLs for all redirects.