Big pictures shown of customizr slider

Hi guys

I´m using the customizr theme and when the slider shows the pictures, which are even smaller than suggested, they look bigger and not proportional..

I´m ussing image sizes even smaller than suggested in the documentation (1170 x 550 pixels)

I´ve also installed the suggested plugin (regenerate thumbnails)

you can see how its working here
http://losportonesdeataco.webstudio503.com/

thanks