Fix JQuery Slider Issues

I need help to fix a website that is having an issue with its JQUERY Slider. The slider is supposed to have a "hover" effect so when the image is in focus (or the user's mouse hovers), then the image is in full color but if its not in focus, then it should be dimmed The problem is that the slider works but sometimes the images are either all full coloured or all "dimmed" or when a mouse hovers and leaves, the image in focus doesn't remain coloured. I am on a very tight budget - looking to either fix the buggy script or have the slider replaced with one that works properly. Attached is the sample of how it should look.