Choose the audience before publishing
Review who can see a post and whether the account is public. Avoid including home details, documents or people who have not agreed to appear. A private audience reduces exposure but cannot prevent an authorised viewer from taking a copy.
Keep a useful original
Store an unedited original and a record of when and where you published the image. For creative work, keep project files and licensing records too. A lower-resolution public export may be enough for display while keeping your highest-quality file private.
Use watermarks for context
A watermark may preserve a credit in casual sharing, but it can be cropped or removed. It does not replace a licence or a reporting process. Place it with readability and the intended use in mind rather than assuming it is technical copy protection.
Respond to a specific misuse
Document the source page, then use the relevant platform process for impersonation, rights concerns or privacy. Avoid publicly accusing the apparent subject of a stolen image. They may also be affected. The image-reuse guide explains how to keep the evidence organised.