Build a Website

I have an issue with my website and I am wondering if you can take a quick look. I am sure the solution is a super simple one but I have no idea what it is, maybe you will find it easy to fix? My website is [login to view URL] I am using a pre bought wordpress theme. The problem is it takes a very long time for the large introductory Background Image to load and the tagline + button to scroll down does not load until the image does which means the user is sitting with a blank screen in front of them for quite a while, unsure what to do, until the image finally loads. I have now reduced the size of the image to 82kb which is really small and should load in a flash. But still the image takes a long time to load when visiting the website. I am really not sure what is up? The other thing is when viewing the website on a tablet, the background image does not scale properly - it looks very zoomed in. Is there a quick possible fix for this? The third thing is that the portfolio (the various images on the front page that can be clicked on to display more content) does not function very well on ipad and iphone. Its difficult to keep the boxes maximised and listen to the songs/videos. Over and above those issues, I would like to ensure overall that the website loads quicker. I need help optimising it. Thanks