How do I display image files as links?

There’s no such “non-coding newbie”-bulk-thing for the process. You have to do that for each of the image, when you are uploading the image to the site and/or post/page.
image linked to external URL

On the right panel of the media upload pane, change “Link To” to “Custom URL” and put the URL (whatever you like – internal or external) into the next text field.

Then whether or not you insert multiple images into the post/page, it’ll link to the link given here.