not a downvoter, had a look at the Outlook site; nearly threw up when I had a look at the source code Outlook.com:
and their css is well... see for yourself.
What I'd do is build a page with two colums of predefined width (can use absolute values in this case). So a class of column width in pixels, and have this assigned to two sections - one featuring the image, and the other featuring the login/ everything else. If the page is resized to be smaller one should appear below the other - which is nice degrading.
You possibly could have an image and a login box without using CSS and somehow configure the login box to be middle aligned with the image - but it's a bad solution and certainly using deprecated code.