How to create read-only ftp access

I created ftp account using this tutorial: http://www.virtualmin.com/documentation/tutorial/how-to-create-ftp-account

but, I am still able to upload files to the server. I just want to allow read-only user so they only can download the file and cant upload any files to the server.

You could use user/group ownership and permissions of the respective files for that, or you can manually use the “Limits” directive in ProFTPD. This might help: http://www.proftpd.org/docs/howto/Limit.html (search for “read-only”).