Okay, I feel stupid right now, but I can't seem to figure out how to change my spark plugs. I (wrongly) assumed that all I would have to do would be unscrew the old spark plugs, but I don't know how to get the old ones out.

This is what it looks like, and I just don't see how to get it out. Any help would be appreciated. Thanks

I knew there was a reason I felt stupid.