From the Super Mario Wiki
A Cragvision in the Gap of Crag

Cragvision is a television found in The Land of the Cragnons. Its name itself is a portmanteau between "Cragnons" and "Television". It was invented by the Cragnons and Cragnons watch many shows here. The Cragvision itself is made of stone that is somewhat shaped like a television set, with what appears to be chalk-drawn images. Oddly enough, these images move; it is not explained how they do this.

Cragvisions give out clues to Mario, Princess Peach, Bowser and the Pixls telling them what to do. For example, the first Cragvision seen in the game has a man running around a Yoshi shaped statue. This was a clue telling the heroes to run around the statue. Other "shows" that may be found on Cragvision is a flame, giving the player a hint that the characters must be used to burn something. The last of the three cragvision pictures is a visual of a person swimming in water, giving the player a hint that the character must swim underneath water.

There is another show that Flint Cragley stars on, called Flint Cragley's Cragtrotter, but it is not seen in-game.