In a lot of cases where the footer's alignment changes, it's due to incorrect tabling or a defined width somewhere that pushes the body of the mailing outwards.
The first thing to do is head to our Resource Center here and take a look at our documentation for using your own HTML. Make sure that all your tags are closed and there's nothing wrong with the code itself.
If you're still finding the footer's alignment to be off, let me know the name of the account you're working in (or if you have the account ID that's even better) and the name of the mailing and I'd be happy to take a look to see what I can find.
We have two primary templates Hospital News BR and Hospital News HV and the photo and text frames are shifted to the left, and obviously not centered. I cannot determine why. Help is appreciated. We do not edit the html, we simply work within the template. Thanks