Edit Ad is very much like Place Ad, except that instead of entering all data from scratch, you will have the Enter Details form pre-populated with all of the current ad data.
The Edit Ad page uses the short code [ AWPCPEDITAD ] (removing the spaces to activate it). The same restrictions on required fields you have with Place Ad are also present on Edit Ad as well.
When you Edit Ad, you follow the same workflow as Place Ad, but without the payment steps. So in order to change any images, you must save your ad details first, and then move to the second step of managing images.