You can upload and unlimited number of listings to Base. There is also no need to remove listings, simply mark them as inactive (sold, expired etc) and access them again later.
The number of active listings (for sale, rent, auction) you can advertise on portals are linked to your Base subscription and individual portal restrictions based on your account.
There is not restriction on the number of photos you can upload per listing. Base automatically resizes listing photos to Full HD resolution (1920 x 1080 pixels).