Trump’s inclusion of a photo taken from a spy satellite in his tweet revealed the resolution and location of the US’ best surveillance satellites. Using the angle of the photo, it was even possible for amateurs to determine exactly which satellite took it.
Forbes – Trump Accidentally Revealed The Amazing Resolution Of U.S. Spy Satellites
Wired – Trump Tweeted a Sensitive Photo. Internet Sleuths Decoded It
NPR – Amateurs Identify U.S. Spy Satellite Behind President Trump’s Tweet