using a snake measuring app:

http://www.serpwidgets.com/Apps/measure.html

and assuming the bucket is 4 feet across

I get somewhere in the vicinity of low 20s.

I don't think there is any doubt it's a big snake, but certainly no where near the holy-grail 30 feet, much less 60.

The bucket is the only thing we can use to distinguish relative size, as it is the only part of the picture that is relatively close to the snake.