Some Prestashop users asked usually how to change the color model picker thumbnail in their default theme.
The way to do it is more simpler than thinking it.
Just find for the following rule in the file /themes/prestashop/css/product.css “#primary_block a.color_pick” and change the width and height as you prefer.
After that you need to put the following rule:
#primary_block a.color_pick img{
width: 50px;
height: 50px;
}
That’s all. Remember to put width and height for the latest rule equal to the one in the first rule (#primary_block a.color_pick).
Another thing to think is the size that must be lower than the original picture size else you could notice some weird result.