Welcome to the "Community.FamilySearch" Forum.
That is a very good and reasonable initial question.
Photographs; and, the like, in fact, much MORE, can be "Added" (or, "Attached") to an individual/person; as, a "Memory", under "Memories" 'Tab' of an individual/person.
Here are some "Knowledge Articles: in 'FamilySearch':
How do I upload memories to FamilySearch?
What rules apply to uploading memories to FamilySearch.org?
Can I add memories about my living relatives to Family Tree?
I hope this helps.
Go to the person page in Family Tree on FamilySearch
Click silhouette or portrait photo
Click Add portrait
Choose or upload photo
Hope this helps!