Conditionally display one of two fields in Display Suite? I'm wondering if there is a clever or preferred way of using Display Suite to display one of two fields.

So my case calls for either an image, if it is uploaded, or a EVA (entity views attachment). I have them both displaying correctly, and of course if the image is not uploaded (unpopulated), then the EVA field displays fine. But if the image is uploaded, I want to hide the EVA field.

I guess I could do a custom code field, but I would like to avoid that if there is a built-in method of choosing one over another field. Maybe something with field groups?

Thanks!
Use the field formatter conditions module: https://www.drupal.org/project/ffc

This will give you the same options that you have on a blocks (and more). So you can show the field based on any url pattern just as you would blocks: 

http://cl.ly/image/2A2Y373Y3e1J

Hope this help.