override create form using activescaffold plugin to build image upload technique

does anyone have ever used activescaffold to build image upload to
database? i'm not sure how to override the form elements in
activescaffold plugin ( good UI rendering for LCRUD) and its difficult
for me to understand where exactly the override technique should be
adopted and how entry screen to be overrided to add image file upload
to DB?>

pls help with some example using activescaffold.

thanks
(Selvan) Kalaiselvan