The slider doesn't seem to expose any kind of events you can hook into, which makes life a little difficult.
A quick fix would be to add this code to the bottom of your HTML file:
sliderPaused = false;
$("#ctgslider").hover(function(){
sliderPaused = true;
}, function(){
sliderPaused = false;
});
Then make sure you are using the non-minified version of the script and alter the NextPicture
function like so:
function NextPicture(e){
if(sliderPaused && !e) return;
Passing the function a reference to the event object, means that you can differentiate between hovering on the slider and clicking the next slide button.
Here's a demo