Start with a work you can document
Keep the original file, export history and publication records for your photograph or illustration. Search a clean copy and, separately, a distinctive crop. A watermark can help you recognise a result but is not proof that the person displaying it owns the underlying work.
Build a source record
Record the page URL, image URL, visible publication information and a dated screenshot. Distinguish an embedded image from a hosted copy. A result thumbnail alone may omit attribution or context that is visible on the page.
Check permission before making a claim
Your work might be used under a licence, by an authorised distributor, or in a context that needs specific legal assessment. Similar composition is not the same as a copied file. The earliest indexed result is not necessarily the first publication. Consult the relevant platform’s reporting process and qualified advice for disputed rights.
Choose a copy-oriented search
TinEye describes its API as finding image uses and modified copies. Face similarity solves a different problem and is a poor substitute for tracing an illustration or product photograph. Follow the original-source workflow to compare the evidence.