Options for when adding link: Hide Thumbnail, Smaller Thumbnail

Basically allow us to choose whether or not we want the link to show a full size thumbnail, hide it, or only make that thumbnail smaller. Some cases ain't so bad, but then there are links such as wikipedia (example: https://en.wikipedia.org/wiki/Swatting#Measures_against_swatting ) where the thumbnail is MASSIVE. And if you have to use two links and both have a preview image, it is much, much worse.