I've been active at Math.SE for over a year and suddenly I can't upload images. When I click the Image icon (when I'm writing an answer) I get a new version of the "Drag and drop or click here" window where the "Drag and drop" picture is divided in 2, with the normal picture on top and an empty white rectangle at the bottom. And if I try and drag a file there (to the normal top part or the new empty bottom part), a new window (message box) appears asking if I want to leave this site. And if I try to click a "cancel" or click the "x" at the top right corner, nothing happens. What's going on?