Non-lossy
From The Glossary of Digital Photography
Also known as lossless. A type of image compression that can reproduce exactly the original image when the image is uncompressed. A lossy image compression achieves its compression by discarding similar data points. Non-lossy image compression does not throw away any data, so it does not typically achieve as high a compression as lossy image techniques. TIFF-LZW is an example of a non-lossy technique. See also LZW
