^https?://(?:\w+\.)?imgur\.com/(?!gallery/|delete/)(\w{5}(?:\w{2})?)\w?\.(\w+) https://imgur.com/$1 $EXTRACACHE <meta\s+name="twitter:image"[^<]*\s+content="([^"]+)"
^https?://(?:\w+\.)?imgur\.com/(?!gallery/|delete/)(?:download/)?(\w{5}(?:\w{2})?)(?![&,]|\w{2,}) https://imgur.com/$1 $EXTRACACHE <meta\s+name="twitter:image"[^<]*\s+content="([^"]+)

これでとりあえずImageURLEx経由して開けるようにはなる