Crazy lady loses crazy art pics

just got app for iPad and macbook pro. i had no problem transferring photos from iPad, both show delivered and received appropriately. However, when the photos arrived at the macbook i did not know how to save i.e.., zip file, medium res, or other. while cogitating about it a window said downld completed. i even gave an album name. the album went to my iPad with no pictures. so now i cannot locate the downloaded pics from the iPad in the mac. also which download format should be used, or what are the differences?