Bonne question je suis preneur aussi,
pour le moment j'ai juste réussi a faire ceci:
il y a bien une histoire d'image dans la classe HelperList
['image'] => 's', // If set, an image will be displayed in this field located in the '/img' subfolder defined as value here (optional).
['image_id'] => 3, // If 'image' is set and if 'image_id' is set, it will be used as the image filename,
http://doc.prestashop.com/display/PS16/Using+the+HelperList+class