Reading the signs
It is well known that paintings are full of symbolism and hidden messages for those 'in the know.'
The same is true with images used online by the shapers of the matrix.
Keep in mind that the matrix that shapes this world is a battlefield. Not all organisations are run by enemy forces. But even the enemy-run organisations have infiltrators who sneak out messages to those surreptitiously, such as in the images they use to illustrate the story.