Lepton is an Dropbox technology which can compress JPEG images by an average of 20%, and often considerably more
The process works by converting the JPG to a more compact LEP format. It uses lossless compression, so pointing the program at the LEP file restores the original JPG.
All this comes in a surprisingly small package, just one tiny console-based executable. Basic usage is simple – lepton.exe pic.jpg or lepton.exe pic.lep to convert from one format to the other – and there are plenty of more advanced switches for those who need them.
If you’re comfortable at the command line, you really don’t need anything else, but for ease of use we’ve also produced a very basic front end.
LeptonGUI accepts files by drag-and-drop or via a standard Open dialog. You’re able to convert everything with a click, and the program displays an overall compression rate and the savings made for each file.
Lepton seemed reliable to us, but be careful: it may still contain bugs. Take the program for a spin, see how well it performs, but don’t delete the original JPGs.