Header banner distorts pictures

Hello everybody, I am uploading a picture in the slider module, in the header position, i crafted the image to the exact same size as the demo on your website, and so, it shows the image in a weird way. Here is the example. http://lanegramente.interactived.co/

Hello,

1) You are using wrong style of the module - you should use the gk_photo style
2) I recommend you to disable the generating thumbnails feature - then the black stripes won't be visible in the image on the sides.