At least in that particular case the image (if not the title) gave you, personally, the information you needed about the video topic. If you know what the Colla

At least in that particular case the image (if not the title) gave you, personally, the information you needed about the video topic. If you know what the Collatz Conjecture is, the image “3x+1” makes the topic obvious. If you don’t, your curiosity is piqued.