To see the hidden image tilt the computer screen, look at the screen from a side angle, step away from the screen, or shake your head really fast. The image is almost completely invisible if viewing strait on and semi close.
I was looking at optical illusions when I came across "John Lennon optical illusion." See link below for the illusion.
I looked on the internet for a tutorial but couldn't find one. After playing around with Photoshop I came up with this Instructable.
Here is the finished file.
This can be done with a photo or text.
- A Photo