you need to get some softwear that allows you to edit your images, and resize them....I don't know what would be best.....I have been using Photoshop for the last 18 years.....you can do pretty much EVERYTHING with it....but its a HUGE program and expensive....there are certasinly some out there that will do what you need that are cheep, or even free. Google search for free photo editing softwear.
here are a few:
http://picasa.google.com/
http://www.photoscape.org/ps/main/index.php
http://www.getpaint.net/
http://www.gimp.org/