Any tips on improving small, grainy digital pics.  I have about 6 pics taken from my Blackberry from the Clapton concert I went to a couple weeks ago.  For some reason, it took all the pics in a low resolution, even though it was set to high resolution.  At high resolution, it surprisingly takes decent pics. 
Anyways, I want to make the pics as good as possible, for posterity's sake.  I don't have any professional programs.  However, I have paint.net, which has a good amount of filters, etc.
Thanks!
Paul