NSFW expando concept feature

It's a simple feature: different colored expandos for NSFW links.  While they already have warning flair and (sometimes) thumbnails, I still find myself clicking on NSFW images without forethought.  I know I've seen many comments about people doing this over the years, so it seems like a reasonable feature.

This is rather quick hack for just image links and using an exceptionally ugly sprite.  I wanted to get some feedback and gauge interest before investing too much time on it.