When to Use
- To express genuine shock at an unexpected piece of news.
- To sarcastically react to something someone said that was obviously untrue.
- To show extreme amazement when seeing impressive fan art or creative content.

Source: BTS
J-Hope from BTS is captured in a close-up shot with his mouth wide open in a exaggerated expression of amazement, with the word 'WOW' overlaid on the image.
People use this image to react to something shocking, impressive, or unbelievable in a dramatic or sarcastic way.