Thread: Upload feature

Can a blog visitor upload an image? If yes, how can I set it up?

You really need to review the Tutorials on how to use WordPress .... what you are asking is one of the first and most basic things you are required to configure .....

By default Registered users can post images, and media unless you prohibit it in General Settings (Global). One special thing about links, is that you can limit the number of hyperlinks Users can post within a Comment, as this helps prevent Spam --- even if you hold all comments for Approval, Spammers abandon attempts if they realize they can place only one per commnet, for if they try to insert more than whatever limit you have set, the Comment is rejected in real-time.

Dashboard > Settings > Media ... this is where you configure allowable image sizes

When a Registered User wishes to post a Comment, there will be a "work box" similar to what you see in your screen as you compose posts, and at the top will be icons to attach images, video, or sound ... just like anywhere else.