webFTP does not change CHMOD

I’m trying to change CHMOD permissions on a folder on my site. Nothing seems to work. Any tips?

I use FileZilla. It says I can change permissions, but will not show the result, so I can’t tell if it worked. I gather this depends on server settings: any idea what I should change?

So I tried using Dreamhost’s WebFTP (https://webftp.dreamhost.com/)
This lets me change permissions, but then ignores what I want. Any ideas?

More details:
I have a PHP file in my root directory that lets people upload pictures, but not see them or do anything with them. (It checks if the picture is genuine first, and renames it). I want the public to have 702 access (I can do anything, they can only write). But the FTP programs keep giving the public full access (707: I can do anything, they an do anything). It’s like the server does not want any security. Am I misunderstanding this? Help!