Do you have Adobe Photoshop?
It seems like you need access to a photo editing program that can find edges, then copy a region to a new image, which you will save as a .png. Then the map will not have the white background, but instead a transparent background. Doing this is a very common practice in photo editing.
If you don't have Photoshop, try Gimp, lots of people use it as an open source alternative to Photoshop.
http://voices.yahoo.com/how-image-background-transparent-photoshop-3642809....
http://voices.yahoo.com/removing-background-photos-gimp-2877803.html?cat=15
Good luck!
steve
Win7 Pro X64 on Dell T3400, MultiTB SATA, 8GB RAM, nVidia FX 570, Vegas 10e (and 11) x64 DVDA 5.2(build 133) Sony HDR-CX550V
