It really looks fine unless you have a wide monitor and view the page at a very wide width. I am only mentioning this because you said you were a graphic designer and it you said you now have to "think of things in a different way" which is refreshing for a web person to hear. Web pages because of their dynamic nature do indeed add some wrinkles to designing graphics so I wanted to throw a little extra info out.
With that said I would either set the site to fixed or maximum width or you could add the following to the CSS Inserts area.
HTML Code:
#imagecontainer {
background-color:#282523 !important;
}
The above code gives the image a background the same color as the background in the image so no matter how wide the site is viewed it will still look OK instead of white.