How to Change my tour thumnail to be larger to fit the list tour container ?

Hi, i added a tour list in my page. And i set it to display only one tour for each row. But when i preview, the tour thumbnail size doesnt become large enough to cover the whole box.

Please have a view here >>> http://prntscr.com/iro81f

The image only become square but in actual the image size is large enough to fit the whole container box.

Please help me.