its not about loss quality because jpeg, it was about hires get lores so images looks 1/4 size in quality for some reason.
Yes Markus, as been told in other threads about this same topic (and you probably know), PDF has not notion of “resolution” on any of the objects used in the document; that is because it is resolution independent. Thus, currently the images are stored always at 75 dpi (you can’t set the “output” dpi for images in a PDF). The loss of quality is because the compression.
Probably other solutions are storing images without compression of the data.
Everything will come along the path… 