An image that has been converted from a lossy image format to a lossless image format. Usually this is a PNG image (Filetype:Png) full of JPEG Artifacts, because it was originally a JPEG.
Lossy-lossless images should not be uploaded to Scrollx when the original is available. It is Scrollx policy to delete third-party lossy-lossless images when the original is available. See Third-Party Edit.