Does anyone know the name of a type of dragonfly whose tail has three
colors, red, white, and blue? These are wide bands across the
tail--one section being red, the middle section is white, and the
third section is blue. I saw these dragonflies near a pond in Guilin,
China. They are so beautiful. If possible, please provide a link
to a picture. Thanks.

I found blue dragonflies, and red dragonflies, and many beautiful
dragonflies, but none matched your description here:
http://www.bjbug.com/insect/odonata/htmE/

Gardenia,
Do check out the site Crabcakes posted.  There are lots and lots of
photos of lovely dragonflies from China.  I was one that was RW&B, but
not as you described, but I didn't look at them all.
Myoarin