> Plotting the savings of 10000 random baseline jpegs converted to progressive, Stoyan Stefanov discovered a valuable rule of thumb: files that are over 10K wil

> Plotting the savings of 10000 random baseline jpegs converted to progressive, Stoyan Stefanov discovered a valuable rule of thumb: files that are over 10K will generally be smaller using the progressive option. At first I thought: "What, you're opening JPEGs and saving them again? Don't you lose image quality every time you open and save in a lossy format?" But then I read the actual source [1], and it says that `jpegtran` can open baseline JPEGs and save them losslessly as progressive JPEGs. That sounds useful! Does anyone know whether other image editing software do the same thing to JPEGs that are re-saved without modification? What about Photoshop? GIMP? MS Paint? [1] http://www.bookofspeed.com/chapter5.html http://www.bookofspeed.com/chapter5.html