Are there anyway to stop WordPress generate multiple image?

Are you sure you want to? You probably have a huge original file, then a 150px square thumbnail, then a medium sized image and lastly a large sized image.

Let’s say you want to display an image within a post. You won’t want to display the huge original, and if you don’t have the smaller sized images you’ll have to rely on browser resizing to display the image within your post. That’s going to have an impact on your site’s performance.

Unless you have a crazy theme that produces several different sizes, I’d leave things as is.

If you really want to stop the behaviour, add something like this to your theme’s functions.php file:

add_filter('intermediate_image_sizes_advanced', 'filter_image_sizes');
function filter_image_sizes( $sizes) {

    unset( $sizes['thumbnail']);
    unset( $sizes['medium']);
    unset( $sizes['large']);

    return $sizes;
}

Taken from: this post at Stack Exchange

Thanks WPRanger. I’ll try this method.