Another translation issue

In last update pot was updated. Make sure to update your .po and .mo

Disable pop-up user profile window

In AnsPress options -> general -> Disable hover card

How to make question page main page

Please read the documents http://anspress.io/documents/

How does the system decide if something is solved vs. unsolved?

No system not decide automatically. An asker or admin can select an answer as best then that question is marked as solved.

Override CSS

Read the documents here: Theme override You can copy whole AnsPress template directory inside your theme and AnsPress will load file from there.

Inserting an Image on categories page

I would recommend icon rather then image, as it we can show it anywhere i.e. in widget. Also you can easily add more font icon to AnsPress fonts using http://icomoon/app Cheers.