>>55891869Different images test for different forms of color blindness. This particular one seems popular on news sites for some reason, it's likely meant to test / control against normal vision.
Depending on which colors the person lacks sensitivity to, different images will be impossible to discern the center image, in this case a '3'.
>>55891893At a smaller size the pink dots act more like conventional pixels, so there is actually more contrast. Adding white space (when the image is larger) requires more color perception to see.
