There was a very popular yet useless trick in the late '90, early 2000 where you'd combine two images in a checkerboard pattern: one at regular intensity, the other very bright (so it doesn't stand out that much upon regular viewing.
Internet Explorer had this feature that if you CTRL+A page contents, it would overlay images with 1px grid to indicate selection. If you got your pattern right, the hidden image would appear. This is essentially the same effect, but on steroids.
Internet Explorer had this feature that if you CTRL+A page contents, it would overlay images with 1px grid to indicate selection. If you got your pattern right, the hidden image would appear. This is essentially the same effect, but on steroids.