Change field_image to field_ad_media

I think this should be discussed. The question is, if the field content is really being reused. I think for banners that's often not the case.
And for specific cases you could just add your own fields. Maybe it's still good for basic installations?

Given how common the image/media use case is, compare to text only, I think we could even have an media entity reference defined in code as a base field.

It also avoids conflicts with modules that use field_image

Thanks for the feedback. I'm still not a too big fan of switching the image field into a media reference field, as I think especially for advertisement the media-reuse is low and the banners used may have a very temporary nature. For that an image field might still fit better.
But of course that's just my experience and oppinion.