LOl! You don't want to leave a print for heritage? 
You can upload whatever quality of image you'd like to your gallery and it will always show a viewable size to anyone looking. There is a 200mb limit (although can purchase more space) so if you want to post a ton of pictures then a smaller file size is a good idea. If you want to use your gallery as a back-up too, then I would recommend uploading full size images and purchasing the extra storage space if/when needed.
You can upload whatever quality of image you'd like to your gallery and it will always show a viewable size to anyone looking. There is a 200mb limit (although can purchase more space) so if you want to post a ton of pictures then a smaller file size is a good idea. If you want to use your gallery as a back-up too, then I would recommend uploading full size images and purchasing the extra storage space if/when needed.