How To Remove Over on Image With Inside Link

Hello Awesome and Great CatchThemes Experts, please take a look at this screenshot: https://dl.dropboxusercontent.com/u/7588358/Screenshot%202017-01-06%2019.53.00.png how can i remove (Catchbox Pro) this background "gray" in this case when mouse is over the element (image) with a link inside? I want to remove on whole blog this background on mouse over all images. Is there any CSS for this? I googled it but no find any working solution. Please help!