Hi

1. The system still creats member by itself

2. When user upload picture it shows as a zip file

What should I do?

1. The system still creats member by itself

This are your spammers, it doesn't have ability to create members by itself. wpForo is not spamming tool, it's a forum plugin. You shoure care about your website antispam protection, this is your most important task as admin. The first thing you should do is configuring reCAPTCHA for all registration and login forms. wpForo has built-in recaptcha, in Dashboard > Forums > Tools admin page. Just use it. Also install Akismet plugin.

2. When user upload picture it shows as a zip file

Use this instruction to display as image:

https://wpforo.com/community/how-to-and-troubleshooting-2/uploading-and-embedding-images/#post-5212

Also I recommend wpForo Advanced Attachment addon.