[TYPO3-english] Varying image on every page

[Rune Tendal Kock]

I'm a newbie to TypoScript, so please bear with me if this is a stupid question.

We would like to have an picture on the top of each page.  This picture should be selectable by the backend editor when editing the page.  I've made room for the picture in our template, and I know how to insert a constant file using TypoScript.  But how do I make it selectable?

If the editor doesn't select any picture, I would prefer to use the picture from the parent page in the page tree.  But just having one default picture for the entire site would also be acceptable.  We use Typo3 6.2 without any extensions or customizations.

Pointers to the relevant parts ot the manuals would be welcome.