Dropbox uses Lepton, a compression format, to encode jpg images and saved storage space. Lepton is a lossless open source algorithm capable of compressing images at 5 MB/s and decompressing them at 15 MB/s. This compression format allows the compression of JPEG images saving on average a 22% of size without losing quality in the process of compression and when it is decompressed the image is exactly the original one. You can imitate to Dropbox and compress your JPG to save space in your cloud servers using WinLep.
WinLep compresses JPEG and decompresses LEP, moreover it can display JPEG and LEP compressed files.
From 2017/01/08, I cannot download it from “http://katfile.com/”.