I have these images that I am getting off my server and a database using PHP
I would try .innerWidth() instead of .width(), as .width() would include the margin.
$('img').innerWidth();
If your image is really that big, you should consider scaling it down it server-side.
Actually .width() is not adding the margin and furthermore its not even adding the padding. That makes .width() more suitable than .innerWidth(). Thanks SKS.