if you use a Windows Operating system on a computer, you can open any picture with the "Windows Paint Program." Then up on the toolbar is a "Re-Size" button.
I have 2 video cameras, a Cell phone Camera and a Digital camera, and each one came with its own software, and each one takes different size pictures, etc....
I've just found it easier personally to use 1 program to manage the color, cropping and sizing for all my pics, and that is the Windows Paint option. It's very easy and it's already installed on every computer with a Windows OS.