Product page image not loading on featured image although it is the biggest in size.Why?

[lalas]

I have a product image that is the first image in the product and is the biggest. But when the product page is loaded a different variant shows up first and not the main image i want. Why is that and how can I fix it.

Thanks

[Shopi5_Coders]

Can you list your URL and password if the site is under development?