When you are saving the multidimensional array you can use this code:
$product_img_path[$count]['wpc_resize_thumb_img'] = $upload_dir['url']."https://wordpress.stackexchange.com/".$resize_img_name;
$product_img_path[$count]['wpc_resize_bid_img'] = $upload_dir['url']."https://wordpress.stackexchange.com/".$resize_big_img_name;
update_post_meta($post->ID, 'wpc_images', $product_img_path);
That way you can get multidimentional array like you want:
Array
(
[1] => Array
(
[wpc_resize_thumb_img] => http://localhost/test/wp-content/uploads/2015/06/Wallpaper_55-212x159.jpg
[wpc_resize_big_img] => http://localhost/test/wp-content/uploads/2015/06/Wallpaper_55-500x375.jpg
)
[2] => Array
(
[wpc_resize_thumb_img] => http://localhost/test/wp-content/uploads/2015/06/Wallpaper_51-212x141.jpg
[wpc_resize_big_img] => http://localhost/test/wp-content/uploads/2015/06/Wallpaper_51-500x333.jpg
)
)