Just using your example
(I am no expert on HTML or XML)
...you might be able to do the bulk of this with the simple "Replace" utility available in notepad
Something like this perhaps:
Find What: <img>
Replace With: /img/<img>
Find What: <description>
Replace With: [CDATA[<description>
Find What: </description>
Replace With: </description>]]
Perhaps far from ideal, but something similar to this may be able to handle some of the "Heavy Lifting"
;-)
JeffCoachman