It depends on the structure of your document (i.e. the article
screen). For example, if you define all or most of your articles will
display a picture in that place, then you better add the image via
Campsite template language, like this:
This works when you have only one image attached to the article and
that's the one you wanna show.
another option... in this case you have several images attached to the
article but the one you wanna show is the number five:
{{ if $campsite->article->has_image(5) }}
{{ /if }}
If the picture in that particular place is not a policy of your
document structure but a specificity for a single or just a couple
articles, then you just might add it via the content editor in the
article edit screen. You have there a "Insert Image" button to do
that.
Either way, first thing you need to do before using template code or
inserting via the editor is to attach the image to the article, you
can do that by using the "Attach Image" box on the right side of the
article edit screen.
Please read these pages on the manual for more detailed info about: