They are complaining that Gimp only allows to save in reconstructable formats (e.g. xcf) even when you opened baked fileformats (in this case jpeg)
In Gimp you have to export to those file formats as you would lose layer and history data as they don’t support that.
ah, yes, saving and exporting used to be conflated. That shouldn’t be a problem, just hit export instead of save
Yeah and then when you close the image it says it hasn’t been saved, which is both annoying and error prone.
Not a super big deal you’d say but when you resize lots of images it is, for example. Especially as it worked differently and one day they forced this bad UX choice.