Product photo and "byuing" panel is scaling wrongly.

On my store i have difficulties to scale product photo correctly, it is now scaling width 50% to product photo and heading panel on right.

Here is detail how it will go on product photo.

This is taken from demo.store:
@media (min-width: 768px)
bootstrap.min.css:7
.col-sm-8 {
width: 66.66666666666666%;
}

This is mine:
@media (min-width: 768px)
bootstrap.min.css:7
.col-sm-6 {
width: 50%;
}

and it looks pretty stupid as image attached. I have try to edit image size from store admin panel, but dont help, how can i get it to work properly? Now all the items details its kind of stupid looking there.