JPG settings in Gimp

[rich2005]

(01-10-2018, 10:39 AM)quand Wrote: Hi

i have a question about a jpg setting in GIMP : "use estimated quality" or "use original picure quality settings"

If I change jpg quality (90 to 95  by exemple), choose optimize and progressive options, what about "use estimated quality" ?

thanks

This is the section from the gimp docs

https://docs.gimp.org/en/gimp-images-out.html  Scroll down to 1.2.2. Export Image as JPEG

Good information there about the various settings. 
Nothing about "use estimated quality" Where does that come from?