Got a content type with some text, and a video field and an image field (and some other stuff, like entity references between nodes, but not relevant for this question).
When displaying nodes for this content type, I don't want to display the image, if there is a video available.
So the image displays if the video field is empty. If a video was added to the node, the image should not display.
Can only be done by modifying the node template I assume? So I would need to copy the node.tpl.php and rename it to node--contenttype.tpl.php (with contenttype being the name of the content type)
But the PHP code in there just prints then entire $content so I cannot interfere with the displaying of the image separately.
Is there another customisation (the one producing the html for the node probably?) where I can wrap some "if" statement around the image field that check for presence of content in the video field?