as the name implies , a lossless compression technique is designed so that the original file exactly as it was . maximum comparisson possible is about 50% . lossless algorithms use some sort of replacing technique ( like RLE or FLAC) .one rough example of replacement would be : 000–1111–222222–333 = 3–0, 4–1, 6–2, 3–3 on the contrary , a lossy compression technique does not allow the original file to be recreated exactly as it was as some detail is lost . As a result it was compress up to 10% of the original file size . example compressed formats would be jpeg and mp3