Try this mod_rewrite rule:
RewriteEngine on
RewriteRule !^uploads($|/) http://example.com%{REQUEST_URI} [L,R=301]
This rule does match any URL path that does not begin with either /uploads
or /uploads/
(leading /
is missing in the pattern due to the path prefix removal when used in .htaccess files) and redirects the request to the corresponding path at example.com.