I am trying to add a picture but the background is white. How can I make the background transparent so it would match my whole page?

You question is in the FAQs but here's a direct link to the relevant topic - viewtopic.php?f=6&t=6616

Unless you're pasting the image, and you're using a Mac. If that's the case, please see this: http://wiki.inkscape.org/wiki/index.php ... or_objects.

Or unless you're saving the file using Save As Cairo png. Instead, the proper way to get a PNG with transparency preserved, is File menu > Export Bitmap.

Sorry for all the what-ifs, but you've included very little info. The topic microUgly suggested might help as well, it's just hard to say, without more info. But we should have you covered through all the possibilities now. If you still have trouble, let us know