Before posting class work or portfolio shots, a small credit mark can help. It is not legal protection, but it can slow casual save-as reuse.
Keep it readable
Use short text such as a name, site, or class code. Lower the opacity, keep decent contrast, and do not cover faces, grades, or QR codes.
Batch with Image Watermark, then spot-check the result list.
Corner marks are common, but leave a little margin. Some apps crop previews and clip the edge.
Pair with other steps
Still strip EXIF for public posts. Compress if needed. Avoid exporting the same lossy file over and over.
Serious licensing or exam security needs a real process, not only a web watermark.
If you will print the work, zoom the preview and check that the watermark does not turn into a smear.
Keep clean originals and save watermarked copies separately. That makes later credit or size changes easier.
Watermarks are applied in your local browser and are not uploaded to our servers. Before a public post, double-check that nothing private sits in the frame.