I'am facing an issue regarding the image thumbnails view, here is the sample website (smartphonewidgets.myshopify.com)
When you click on a product variant image, the browser show up the featured image instead of the variant one.
How could I resolve this please ?
If you are looking to select one of your variants when a variant image is clicked, Shopify has some documentation for this along with code snippets - Select Product Variants by Clicking their Image.
Depending on your theme, the code snippets may be cut/paste or you may need to dissect them a bit and adapt them for your needs.