Feature image stopped working

I currently have the Highend theme installed on my site but the other night the main image behind the text disappeared and nothing seems to work to bring it back. In the edit page the picture is showing as being set as the featured image, i’ve re-uploaded the image and also tried images but nothing appears.

I’ve also just noticed that under Reading Settings I’ve selected a static front page but in the drop down box for Front Page the home page doesn’t exist, it just displays -Select- . Will this be the reason why it may be happening?

Can someone please help me solve this problem?