The website for Louise Billgert, a Swedish photographer. It is no longer online, but it was there for over 15 years, not a lot of websites are that old!
The site had a function were you can turn on and off the details and also go to ‘passepartout’ mode, where you only saw the image (and the details, if they’re turned on). In the second image, you can see the details turned on and on the third image, you can see the passepartout mode.