Any way to delete an asset from a metafield type: image field?

I've set up a number of metafields with type: image. They work as expected.

However, if I add an image to a particular field and then decide I no longer want an image applied to that field, there is no way to delete the image. I can delete the image from the Assets section of the Admin panel ("Back Office") but what if I don't want to do that? What if I want to retain the image to use elsewhere but simply don't want it applied to my metafield?

There doesn't appear to be a solution at this point.