image quality get worse when selecting an attribute image on the cathegory page

the problem is more visible on mobile bvrowsing.
Exemple page: https://www.raffoslab.com/shop/tokens/tokens-tokens/
on tokens with choice 1-5 1-10 , is selecting the 1-10 attribute that as the same image as the original it gets blurred with big loss of quality.
tested on chrome android browser
tried changing also the swatch image resolution up to 2500px without any improvement