By pixel count 16 Mp to 2 Mp throws away 85% of the pixels.
You can not keep the same level of detail and quality.
Edit: I was a bit terse there, much depends on the image and the intended use.
This comparison in an image viewer and the downscaled image does not look too bad. https://i.imgur.com/UxNhYlS.jpg
Only when you zoom in does the loss of detail show, those stepped pixels. https://i.imgur.com/zin6tmb.jpg
In Gimp that looks worse. Image viewers / web browsers will 'improve' an image with a little blur. All in the eye of the beholder.
I pulled out a good ImageMagick down-scaling function
..and really no better than Gimp NoHalo algorithm.
You can not keep the same level of detail and quality.
Edit: I was a bit terse there, much depends on the image and the intended use.
This comparison in an image viewer and the downscaled image does not look too bad. https://i.imgur.com/UxNhYlS.jpg
Only when you zoom in does the loss of detail show, those stepped pixels. https://i.imgur.com/zin6tmb.jpg
In Gimp that looks worse. Image viewers / web browsers will 'improve' an image with a little blur. All in the eye of the beholder.
I pulled out a good ImageMagick down-scaling function
Code:
magick image.jpg -colorspace RGB -filter Lanczos -define filter:blur=.9891028367558475 -distort Resize 34% -colorspace sRGB downscaled.png..and really no better than Gimp NoHalo algorithm.