As of yesterday, a new image uploader has been introduced. This new uploader, while fitting in with the principles of responsive design, is causing quite a few glitches in a lot of different platforms. In the hours since it was rolled out, there have been two documented cases of it not working at all in certain platforms. (Both those links refer to the same platform, but the presence of a duplicate indicates how widespread it is.) Additionally, the "link from web" option is non-intuitive, doesn't work at all on Internet Explorer 11, and currently suffers from a focus bug in Chrome and Edge.
While these bugs are being sorted out, I think there should be a way to temporarily revert to the old upload UI. Since it's intended for responsive design, I suggest that if the user chooses to disable responsiveness, the old upload UI be shown instead (since responsiveness isn't important if it's disabled).