An image containing the word "Sample" (often in all caps) as a watermark anywhere on the image, typically covering the entire image. In Japanese, the word for sample is サンプル, さんぷる, 見本, or みほん.
Such measures are typically used on "sample" images of products (posters, cards, dakimakura, etc.) to prevent counterfeiting.
Pixiv
Twitter
Bluesky
Weibo
Lofter
Tumblr
