It looks like there is a recent bug with the Google knowledge panel images that some are actually missing. It was working fine a couple of hours ago, but right now, the images for many are simply blank. I assume it will be fixed soon.
The image above is for a search on [rustybrick] – it should show this in that image box white area:
But right now, it is white and blank.
This was reported first about 45 minutes ago in the Local Search Forums and I suspect it will be resolved and fixed soon.
Forum discussion at Local Search Forums.
Update: If you shift refresh, you may now see the images show up in that location now.
