The memories shown are ones that YOU have uploaded to your gallery. No one except for you, can see these memories, UNLESS you have tagged those memories to FamilySearch deceased people. The important point here is to make sure that you TAG your uploads to individuals. If you do not tag your images, then when you are deceased, none of the photos in your Gallery will be available to others to see!
WHAT IS "TAGGING?"
Tagging is a way to attach a photo to one or more individuals on that image. For example, you will commonly see a small rectangular box around a person's face with their name underneath as you hover over parts of the image. This allows others to know specifically who is who in the photo.
If you forget to tag your images, FamilySearch has added a small "Add Tag" notation in the lower left part of the image to remind you that the specific image needs to be "tagged".
From FamilySearch Helps:
If you contribute many photos, stories, documents, and audio files to FamilySearch, your gallery can become so full that is difficult to manage. If you have finished tagging the memories and titles, descriptions, event dates and places, and other information, you can move the image to your archive to declutter your gallery.
When you archive memories, they remain online for others to see. If you have tagged them to a person in Family Tree, the tag remains, and other users can still see the memories. The only thing that changes is that you no longer see the memory in your gallery.
When you view your archive, you can see the memory, edit it, add it to albums, share it, and do all of the other things you could do from within your gallery. You can also move it back to your gallery.
Albums are a powerful way of collecting groups of memories into one collection. There are no set album names. You can create them based on your needs. For example, let's say that you are going to have a family reunion and want to show some photos, play some audio recordings, and maybe show a few documents on both LIVING and deceased family members. Create an album such as 2021 Family Reunion. All you need to do is assign those memories to that album.
Assigning your memories to an album is the easiest from your Gallery page. You can select MULTIPLE items (right upper circle on memory when hovering over it), click on the Actions link, and "Add to Album" action.
If you click on your album, either from the Gallery Page or the Memories Page, you will see a menu as seen below. Notice that you can create a "Slideshow" as an option as seen in the far right of the menu.
Be sure to SHARE your album with family members. The two most common share options are sharing a link through email, or copying the link and sending in a messaging app or via email. With that album link, they will have access to the album, even without having to log into FamilySearch.
Use the various menu bar filter tools along the top to filter the type of content you want displayed in the content area. You may want to only see photos, or stories, or audio, etc in the content area.
There are options available that are initially hidden until you hover over the content images. A small circle will appear in the right upper corner that allows you to select the content you want. Once you have selected at least one item, a blue menu bar appears above the content area with an "Actions" dropdown button on the left side.
Options available after clicking on the blue Actions link are noted to the right.
Rotation: Most of the menu options are self-explanatory. Occasionally you may upload a rotated photo. Rotate right or left helps you to fix this.
Download: This is where you can download a photo or other memory that you would like to save on your computer.
Change to Document/Photo: Let's say you have a jpeg image of a birth certificate that accidentally gets put into the Photos Section. It really is a document technically, so the "Change to Document" allows you to move the image into the Documents Section.
Move to My Archive: If your Gallery page is filling up with memories, then you may want to move some of them to "My Archive". Typically, you can fairly easily see up to about 1500 images, depending on the memory available in your computer. If you have completed all the Tags, adding in dates, places, description, etc for the memory, you may just want to place the image into "My Archives". They will still show up in Family Tree. You will just not see them in the main gallery content area. Think of the Gallery as a "Working Area", such as importing, tagging, entering in information, etc. Once you are done with all of this, you can move them to the Archives if desired. This also improves loading times for all the memories when you first go to the Gallery page.
Add to Album: You can add the image to an album, as well as look at all the different albums that you have assigned a memory to. (You can have an image in multiple different albums.)
Topic Tags: These can be added here to a memory or on the Memories Page. The advantage of applying them from this page is that the topic tags can be added to multiple memories at the same time, rather than one memory at a time.