cached related product images 200x200px not "perfectly" compressed

opencart version 2.3.0.2
Default Store Theme used

Cached related product images are not "perfectly" compressed according to G page speed insights:
"Compressing https://www.xxx.xx/image/cache/catalog/ ... 00x200.jpg could save 1.7KiB (19% reduction)"
...

Any help would be really appreciated, thank you in advance.

You might want something like this : https://www.opencart.com/index.php?rout ... n_id=18138

Our catalog product images are perfectly compressed.
It is just the cached pictures, which are generated automatically by opencart and saved to the cache folder which are not perfectly compressed.
The extension "Image compressor" would not help here I guess, thank you nonetheless.

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