The use of images is one of the best tools for an escape game builder and can be used in many ways as a starting point for a game task. Below are a couple of examples where a code is extracted directly from images:
If you have a four-digit lock, for example, you can use a picture showing items in four colors. The container picture, for example, has the colors blue, brown, teal and beige. Players add up containers of the same color and thus get a number for each color. The order of the numbers can be indicated somewhere else, e.g. by gluing four color pencils of the same colors in a row onto a desk, book, paper etc.
The container image is challenging because the its colors are not basic colors but nuances. Men in particular easily interpret brown and beige as brown. Similarly, blue and teal are interpreted as blue. Women, on the other hand, see and name the nuances of color better. Bear this in mind to increase or decrease the challenge of the color task.
Alternatively, you can search for an image where the colors are insidiously set up as the number or letter itself. For example, the image below could easily be interpreted as zero or the letter O.