Reaction images are a cornerstone of internet culture, serving as visual shorthand for emotions that text alone cannot capture. Originally gaining traction on early imageboards like 4chan and Something Awful, they evolved from simple emoticons into high-definition screencaps from movies, TV shows, and viral videos. Unlike traditional image macros with fixed punchlines, reaction images are versatile tools used to respond to news, social media posts, or group chat messages. They range from the iconic Shocked Pikachu to the skeptical Side-Eye Chloe, providing a diverse vocabulary of expressions that allow users to communicate instantly with humor, sarcasm, or relatability across all social platforms.