Product thumnail image gets darker on mouse hover

-- url of the page with the problem -- : www.gojollyfashion.com/index.php/category/14-mangal-sutra
-- HikaShop version -- : 2.6.1
-- Joomla version -- : 3.4.8
-- PHP version -- : 5.6.17
-- Browser(s) name and version -- : IE?CHrome

Hi, Please see attached images to under the issue:
Image: productthumnail-beforemousehover.PNG -
What is seen to end user: Product image thumbnail

Issue: When user tries to click on the thumnail, nothing happens.

Image: productthumnail-onmousehover.PNG
What is seen to end user: Thumbnail image pops up with black background
Issue: On mouse hover, user sees the image background goes to darkish black. Not a good user experience.

Please help resolve to remove the thumbnail image getting darker on mouse hover. Below is link of one of the products: www.gojollyfashion.com/index.php/category/14-mangal-sutra