XnView Software

In order to minimize generation loss upon resaving JPEG images, the following setting was introduced in version 1.90:

• Tools » Options... » Read/Write » Write » JPEG » Write » Parameters » Use estimated original quality if possible

I was hoping this could be added to the dialog of File » Export... » JPEG, too.
I would also like to suggest that activating the checkbox automatically changes the parameters for Quality, Smoothing factor, SubSampling factor, and baseline vs. progressive DCT to match those of the original file.

Related topics:

• JPEG compression as lossless as possible
• Save JPG At 'Original' Quality
• Options->Read/Write->JPG: Use estimated Quality