Ah, I recognize those images.
They are Hotmail's "placeholder" pictures when there is no image, and unfortunately we can't tell them apart from actual user-set images.
The app's code to fetch profile images from Hotmail hasn't changed. I just tried my Hotmail account in Aqua and got same "placeholder" image.
Must be a Hotmail issue, and a recent one too.
Microsoft just finished moving Hotmail / Outlook.com to a new technology platform on the back-end. A bug or a few could easily go unnoticed.