Hi,
The description is taken from the main product with the code I gave you. If that's not the case, it would mean that the variant has a description of its own (maybe just a HTML tag with no text in it (some HTML editors add that).
For the image, change the line:
$checkfields = array('product_name','product_description','prices','images','discount','product_url','product_weight','product_weight_unit','product_keywords','product_meta_description','product_dimension_unit','product_width','product_length','product_height','files','product_contact','product_max_per_order','product_min_per_order','product_sale_start','product_sale_end','product_manufacturer_id','file_path','file_name','file_description');
to:
$checkfields = array('product_name','product_description','prices','images','discount','product_url','product_weight','product_weight_unit','product_keywords','product_meta_description','product_dimension_unit','product_width','product_length','product_height','files','product_contact','product_max_per_order','product_min_per_order','product_sale_start','product_sale_end','product_manufacturer_id');
in the file administrator/components/com_hikashop/classes/product.php and that should help.