example does not work : ' recordset'  undefined, image not available

The example shown at https://python-docx.readthedocs.org/en/latest/ does not work.
it assumes an image to exist, and the variable "recordset' does not exist.
You might want to consider adding a working example like the one referred to the install, 
so people can test if all went well.

Or maybe I'm not bright enough to find these examples... 

Keep up the good work !
