Finding hidden images

Every pixel is made of red, green and blue values from 0 to 255, and each value is stored as eight bits. Changing the lowest bits barely changes the color, so a second picture can be hidden there where your eye cannot see it. Viewing one bit at a time, called a bit plane, makes it jump out.

Start with "All bit planes" and look for any square that shows shapes or writing instead of static. Click it to see it full size. Other views help too: "Random colors" gives shades that look the same completely different colors, which reveals text drawn in almost the background color, and "Boost contrast" brings out faint marks.

Pixel colors

Click any spot on the image to see its exact red, green, blue and alpha values and hex code. Some puzzles hide numbers or letters in pixel colors, like a row of squares whose red values spell out coordinates.