This photo was taken in Clear Springs, Mississippi, using a 100mm Macro lens and Canon Rebel T3i. This is, I believe, an orb weaver, hanging upside down from his web. This spider was actively spinning his web when I happened to spot him on the side of a walking trail! This spider, believe it or not, is quite tiny!
I believe this spider is actually cutting silk in the process of creating a web. You can also faintly see small hairs on the spider's back legs, which help the spider feel when a bug is trapped in the web! This image was shot at 1/125 seconds, and you can see small segments of silk flying in the air as the spider cuts the web.
If anyone knows more about this process, please comment below!
Watch this cool video of a spider weaving a web: http://youtu.be/kn83aC7NjSc.