explain the error please

Hello,

We were trying to check our website http://cashadvancesus.com/ through your
validator tool and it showed the following error:

   1. Error Line 316, Column 259: general entity "h" not defined and no
default entity

      …es/categories/cash-advance-online.jpg&h=97&w=201&zc=1" alt=""
title="Cash Adva…



      This is usually a cascading error caused by a an undefined entity
reference or use of an unencoded ampersand (&) in an URL or body text. See
the previous message for further details.


As we understand 'h' stands for the height of the image and it's Wordpress
that generates it this way.
Can you please explain what caused this error?