A post whose source is a direct link to a Huaban image, rather than to the Huaban post containing the image. These are considered bad links because there's no way to find the original Huaban post from the image link.
If you see this warning while uploading, it means you should paste the link to the Huaban post on the upload page, not the image itself. Though consider checking for alternative sources first if possible, as Huaban posts are often third-party sources of lower image quality.
