Posts could show preview images

[HeikkiNaski]

It would awe-inspiring to have a preview image fetched when a link is added. It would be ripping to be able to remove that image if desired. It would be unearthly to be able to show an arbitrary preview image next to the post.

e.g. I want to link to a good blog post, but by default the system will get the bloggers mug shot. He doesn't look very nice, so I want to have as the preview image one of the diagrams the bug-ugly blogger was using in the post.