This tag indicates that an image sourced from Tinami is sampled, and is not the original image.
Many images on Tinami have a preview image and a fullsize image, with the preview usually having a max width of 720 px. The image URLs for both previews and fullsize are structured the same.
It is Danbooru policy to either replace samples or delete them. See image sample for more information. See howto:tinami for how to upload images from Tinami correctly.