Bigger colour picker pictures

[marblemsn]

Hello,

 

I am new to Prestashop!!!

 

My internet site is rajastones.co.uk, and I have very small colour picker thumbnails. Is there any way that these can be made larger. I am trying to sell stone, but the detail is missed with such small humbnails.

 

I have looked at the Preferences tab and then the Image tab, would this give me larger a Colour Picker. I am nervous in making changes.

 

Any help would be appreciated.

 

Thanks

 

K