Gray Overlay over Images in Featured Slider

Hi Team, I am using Foodoholic Pro<span class="theme-version">Version: 1.7.3 and want to use the Featured Slider Theme Option.</span> I've activated it, chose some images, so good so far. The problem is, that it seems like there is a color-cast/overlay on top of the images, what ruins it for me. I can't find an Option do deactivate an overlay or something.   I can't provide a link to the side yet, cause it isn't public yet.   Just imagine a clean white image as one slider image but it appears gray.   Kind regards