Momentum: Make white background header appear against certain artwork?

I'm wondering if it's possible to make a white background header appear on my site when against complex, coloured background images?

My website is: http://www.jamie-kirk.co.uk

Any help would be appreciated.

Thanks for getting back to me @Paul2009, I've tried the code using the URL of a specific image that I'd like a white background to appear on the header, but this doesn't seem to work?

See attached image of the second gallery image on my website as an example of how the header/logo isn't visible against this style of image - I'm wondering how I can apply a white background to specific images included in the gallery?

Thanks in advance

See attached image of the second gallery image on my website as an example of how the header/logo isn't visible against this style of image - I'm wondering how I can apply a white background to specific images included in the gallery?

Thanks in advance