I hate the "Common" adjective in bird names, and it isn't much better in dragonflies. C'mon, animal-namer-people, get a thesaurus and try a little harder, will 'ya? Instead of Common Whitetail, how about something like Pied Whitetail or Zone-winged Skimmer?
I had this striking dragonfly in my backyard a couple of weeks back. Interesting to see how lining it up with different backgrounds changes the overall feel of the shot. The trick with the darker backgrounds was to avoid overexposing the bright abdomen. On the pic with the darkest background I had to compensate -1.0.