Advice needed for including images in epub

Hi all,

I’m using Scrivener for Windows to compile my first ebook for publishing to Amazon. I’ve asked my cover designer to give me some interior artwork as well -title page, chapter headings and scene dividers. I’ve just copy and pasted these into the text, however they are displaying as aligned slightly to the right of the centre when I view the epub on my iPhone.

Was hoping someone could advise on what I might be doing wrong here?