Looks like there's a kind of dot pattern in the stars appearing when changing exposition and saturation.
You must save the picture and then open it and zoom, it's the original size.
Basically I just increase exposition nearly to the max and then play with saturation.
Reminds me the dots on an other picture
I have simply used Colorsync on Mac, put the exposition cursor at 90% and then increased saturation. The pattern appears with more or less dots according to saturation level. If it was a real picture all stars would have the same dot pattern after altering the picture, so I think there's a message. Unfortunately I'm not skilled enough to set it clearly.