Another result of many experiments in Gimp/G'mic.
Beware: "polygonize" technique not applied manually gives sometimes unpleasant results.
But -you know- I'm a lazy filter man, I don't aim at creating magnificent results doing the steps manually, I prefer more modest results but repeatable when the user (myself in primis) wants so.
Here the filter, hoping someone may like it anyhow and test it:


Update: (Febr.22)
This is a new version, it does not override the previous one, just another "preset" (as Lyle calls them) for those interested.

The filter has an option to get:
- strong polygons borders
- weak polygons borders
- no borders
A set from a landcape source, in the 3 variants.

A set using flowers:

A set using a portrait as source image:

Amico Dinasset, you are such productive about artistic effects. I'm really impressed with this one, too. It's great!
Here, my first results,

Thanks my dear friend! I like your creations.

Excellent plugin, thanks dinasset! Being a vector dude I like the outcomes.
Initial test on the favorite pexels image, using borderless option.

Thanks Nidhogg, very nice outcome.

Three no-borders outcomes.

Dinasset, you did an excellent job in this polygonize effect. I love it.

Issabella, your Tom Hardy is perfect!

My attempts with post-process.

Definitely more appealing results than using G'MIC's polygamize preset alone, Diego. See a lot of potential with this one. Though i would turn my Christmas cactus capture that I did a few years back into folding aluminum.

Thanks Lyle.
With your creativity you'll find pre- or post-process steps to get some of your interesting manipulations.

A dream.