Make a view or panel that displays image *or* video field if present My goal is to have a content type that will display an image in a certain panel pane or an embedded video, if the video is present.

I can imagine setting up two fields, one for the image and one for the video embed code. But I'm not sure how to hide the image if the video is present or to make the video field take precedence over the image field in panels.
It can be done with Views rewriting options. 


Add both fields (Image before Video) to Views and exclude Image field from output.

For Video field set “NO RESULTS BEHAVIOR” to Image field token:



It means that if Video field is empty Views will get value from this textarea, which contains special placeholders (in this case [field_image]).

Available tokens for your fields can be found under “REWRITE RESULTS” fieldset:


Don't forget to uncheck “Rewrite the output of this field” flag.