thanks @andheum and @Carsten_Rodin for the feedback yes i would love a checkbox either because very mostly i would only drag and drop an image for a picture frame into the viewport. Textures also work without popup when dropped onto an object. Dropping an image into the empty space should mean either Picture frame, Wallpaper or Environment, but the last 2 are rather rarely used i at least never use them.
Maybe there is a way activating the pop up with alt while dropping? Might make more sense for the general use. @dan would that be worth considering? at least for the final release of Rhino 6 for Mac.