[Mone']

this can be easily done using css

for the reply box look for this bit of code in the custom template
showthread_replybox

<textarea name="message" rows="7"  cols="$textareacols" wrap="virtual" tabindex="1"></textarea>

and chage it to :

<textarea name="message" rows="7"  cols="$textareacols" wrap="virtual" tabindex="1" style="background-image: url('http://www.yourdomain.com/images/background.gif')"></textarea>

were : 'http://www.yourdomain.com/images/background.gif'
is the url of the image that you want to show in the background


if you any problem let me know as i got working 100%

Mone'