How to add a custom field for image in “Text and Full Image(text right)” layout?

I need add another image in the standard “Text and Full Image(text right) layout” in WordPress. This layout by default has a field for an image. I located the php file that renders this page which is text-and-full-image-text-right.php Is there a way I can add a new image field in this standard layout? The Screenshot below shows you where I need to place my new image. I know how to use custom fields in a template, but not sure how to use them in the layouts/rows in the edit screen?

Reinstall WordPress while keeping attachments

I have a WordPress installation that I want to reinstall. However, I also have in it several uploaded files (.doc and PDFs) that are linked by external sites. They are not used in any of my own pages: I just uploaded them to my WordPress site instead of putting them in a Dropbox or a Google Drive, and now I can’t (or shouldn’t) delete them.