How do commenters upload their image
I've just installed almost every add on from wpDiscuz and I do not see how a commenter is able to add an image or comment as anything but an anonymous guest.
If you install the wpDiscuz Media Uploader add-on the button for uploading the images is located at the right bottom of the editor, as shown in the screenshot.
comment as anything but an anonymous guest.
I'm sorry, but I don't follow you. You'd like to implement the anonymous commenting feature, wouldn't you? If yes, please navigate to Dashboard > Comments > Forms admin page, edit the Default form, then click on Email and Username fields edit buttons and find uncheck the "Required" option. In this case, if the users don't fill their name in the name field, it'll show as Anonymous.