Since someone already offered to do it for you, I'll just refer you to two free programs you can download to resize pictures: The first Picaso is sponsored by google and does a lot more than just resize, it is a very handy photo editing program and the resizing feature is easy to use:
Picasa 3: Free download from Google
The second is just a picture resizer, very easy to use:
Image resizing, do it with PIXresizer
There are also places that do it for you online, where you do not have to download a program. I haven't used any of them before so can't recommend one over any other. I can definately recommend Picaso. I think I used it more than my PSP.