A grey area towards the lower part of an image usually signifies a corrupt or incomplete image.
I notice that the actual image files on your web server (at least the ones I have checked) appear to be OK and the problem seems to occur only within the gallery.
It looks like something is preventing all images from loading completely within your gallery. It could be something like a server timeout value.
I notice that some of your images are over 1MB each and have a resolution of 1620 x 1080.
With the default value of 'PAGE' being used for the imagePreloading configuration option and 14 thumbnails being displayed per page, the user's browser may be having to preload upwards of 10MB of data as soon as the gallery is displayed. This might be causing timeouts on some images whilst they are all being preloaded.
Try setting imagePreloading="NEXT" (in svBuilder-Pro's 'Customize -> Main Image' section) so that only one image is preloaded when the gallery is first displayed.
Alternatively, try reducing the filesize and resolution of your images to reduce the load on the user's browser when the gallery is first displayed.
If you allow svBuilder-Pro to resize your images using the default settings of 1024 x 768 at 80% quality, the resulting images should have a filesize of around 120KB. This is much smaller than your current image filesize but should still be of sufficient quality for web gallery usage.
Hopefully this will help.
SimpleViewer Support Team.