Interesting fact: one of the powers of the President is to declassify basically anything at any time, without any process, merely by revealing it [0]
0. https://www.politifact.com/truth-o-meter/statements/2017/may...
0. https://www.politifact.com/truth-o-meter/statements/2017/may...
It might be okay if experts conversed with the president about the second and third order effects of tweeting the image, and he concluded that it was worth it to release the image. However, given the widely reported disdain that he has for the intelligence community I doubt that such a conversation took place.