Field name where image is stored ?

Didnt get any solution yet on how to use YAPB with SNAP to auto detect featured image ,but there is an option in snap where we can add custom Field names and it can use it as Featured Image , so which ones are that ?

THE SNAP SETTINGS ARE :
Custom field name:
Set the name of the custom field that contains image info
Custom field Array Path:
[Optional] If your custom field contain an array, please enter the path to the image field. For example: [‘images’][‘image’]
Custom field Image Prefix:
[Optional] If your custom field contain only the last part of the image path, please enter the prefix

Anyone in knowledge of this ? because i am sure if field names are known this might solve the featured image issue .. no need to do double posting

http://wordpress.org/extend/plugins/yet-another-photoblog/