[1Old Pro]

And you are forced to click the OK button to close the screen.

That's to confirm and implant their spy software.

[SaveFerris]

Could well be true

I wrote software with hidden stuff in your emails

Code embedded in a single white pixel on your screen

Nothing nefarious in intent but we could gather certain basic information

Because it was embedded in a single pixel (or multiple pixels, graphics) you’d have no idea that it was even there