@Sesh1014: First your logo it too big that is why it is showing a large space in the header. If you have edited any core theme files then all the changes will be gone when you do the update. So, if you just want to change the css then you can add the css in “Custom CSS” box in your Theme options. But if you want to further customize the theme then you can build child theme and do the customization. If you follow any 2 steps then you will not lose your edits while doing updates.
The Featured side is showing fine if your site. But for the features slider if you upload the larger image then it will look great. See the image size needed in Theme Instructions http://catchthemes.com/theme-instructions/simple-catch
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