Add images/icons to links (depending on source)

I’m not sure if this is WordPress specific at all (whether there’s a plugin of sorts, or if this is doable through basic coding), just to give you all a heads-up.

Check the first paragraph of this post for what I mean. There’s a video symbol before the links because the source URL is a youtube.com address.

In my case, I’d like a photo/camera symbol before any link that goes to Flickr, i.e. has flickr.com in its source URL.

Any clues on how to achieve this?

PS – I noticed that Apture is used on the example blog above. Is that the only way to get the icons to show up? I don’t really want the preview pop-up, just the icons.