Hello, and thank you for your responses.
@gpatel-fr
Your picture looks good to me. And NO, my picture with 12.6MP is usually between 2 and 3MB, but that could depends on the details on the image.
I think that the issue become more apparent with a little bit of zoom, let say 10-15% of the zoom bar (almost no zoom).
So:
Image resolution: any, usually 12 or 12.6MP
Quality: any, but I let it in "Fine"
Flash: no, private: no, Geo: yes, but not sync.
A little bit of zoom.
Here is a comparison of the two images side by side:

You can see that the detail between the 3D-printed passes are much less visible, most dust has disappeared, and if you zoom the image, details seems like if it was an SVG image (no pixels with noise, but rather small areas with flat colors).
I have several hypothesis:
- The image is saved always with an aggressive compression, indifferently of the Base/Normal/High/Fine quality.
- The picture is passed through some beautifying filter intended for people.
- Some image anti-noise filter is not adjusted properly when using the zoom.



