Disabling featured images;

Hi there. I center my images which are all featured; you see, when you use the built in excerpt option, the featured images go the way that the theme intends. I then found a plugin that's called advanced excerpt. What it does, it shows the default featured image and the original image at it's proper size, though two images show up; look at my site gadgetxpert.co.uk, I want to remove the featured i,ages, do you have a custom CSS?